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White Paper
Competitive Management Cost Study:
IBM Storwize V7000 vs. EMC VNX5500
Storage Systems
April 2012
Printed in the United States of America.
Copyright 2012 Edison Group, Inc. New York. Edison Group offers no warranty either expressed or
implied on the information contained herein and shall be held harmless for errors resulting from its use.
All products are trademarks of their respective owners.
First Publication: April 2012
Produced by: Kalicharan Rakam, Senior Analyst, Craig Norris, Writer; Barry Cohen, Senior Analyst,
Editor-in-Chief; Manny Frishberg, Editor
Table of Contents
Executive Summary ..................................................................................................................... 1
About This White Paper ............................................................................................................. 4
Who Should Read This White Paper ................................................................................... 4
Methodology Overview......................................................................................................... 4
Contents of this White Paper ................................................................................................ 4
Storage Management Costs in the Data Center ..................................................................... 5
Overview of the Products ........................................................................................................... 6
Overview of the Management Consoles ............................................................................. 7
Results Summary ....................................................................................................................... 13
Comparative Management Cost Savings .......................................................................... 15
Results Details ............................................................................................................................ 18
Provisioning .......................................................................................................................... 18
Data Protection ..................................................................................................................... 21
Maintenance and Configuration Changes ........................................................................ 24
Monitoring ............................................................................................................................. 27
Methodology for This Study ................................................................................................... 31
CMCS Methodology............................................................................................................. 31
Laboratory Configuration ................................................................................................... 31
Test Procedures ..................................................................................................................... 33
GUI vs. CLI ............................................................................................................................ 34
Other Considerations ........................................................................................................... 36
How to Use These Results ................................................................................................... 36
Conclusions ................................................................................................................................. 37
Appendices .................................................................................................................................. 38
Appendix I - CMCS Methodology Description ................................................................ 38
Appendix II - Terminology Glossary ................................................................................. 42
Edison: Comparing Management Costs for IBM Storwize V7000 and EMC VNX5500 Page 1
Executive Summary
As it has been the trend over the last decade, organizations must continue to deal with
growing data storage requirements with the same or less resources. 1 The growing
adoption of storage-as-a-service, business intelligence, and big data results in ever more
Service Level Agreements that are difficult to fulfill without IT administrators spending
ever longer hours in the data center. Many organizations now expect their capital
expense growth for storage to be unstoppable, and see operating expense levers — such
as purchasing storage systems that are easy to manage — as the only way to control data
storage-related costs.
Edison’s Competitive Management Cost Study (CMCS) methodology was designed
based on Edison’s research over several years. It quantifies the complexity of managing
a storage array in a way that easily translates into operational expense. The present
study applies this methodology in comparing the relative complexity and ease-of-use of
management consoles for two storage systems built for mid-sized organizations: IBM
Storwize V7000 and EMC VNX5500. While the two products compared in this study are
both unified storage systems, this study specifically evaluated only their block-based
storage features.
The results of Edison’s research show that administering the IBM Storwize V7000 system
using its management interface is 34 percent less time-consuming in weighted workday
savings and 31 percent less complex than managing an EMC VNX5500 system using the
Unisphere software interface. These results are displayed graphically in the following
graphs.
1 Gartner Expects Mild IT Spending Growth in 2011, Enterprise Storage Forum.com
Edison: Comparing Management Costs for IBM Storwize V7000 and EMC VNX5500 Page 2
Edison: Comparing Management Costs for IBM Storwize V7000 and EMC VNX5500 Page 3
Using storage administrator-workload weighting factors developed by Edison, these
time savings can be evaluated in terms of operating expense (OPEX) savings. This
assessment demonstrates a 34 percent improvement 2 in storage administrator efficiency
from IBM Storwize V7000 over EMC VNX5500.
Monetizing these efficiencies can result in cost savings of more than $25,000 per year
with IBM Storwize V7000 over EMC VNX5500.
2 Presented in Table 1 of this report: Storwize V7000 CMCS Summary of Results.
Edison: Comparing Management Costs for IBM Storwize V7000 and EMC VNX5500 Page 4
About This White Paper
This white paper is based on a combination of hands-on evaluation, review of relevant
published documents on storage cost of ownership, and reports on data center and
storage administrator salaries.
Who Should Read This White Paper
This white paper should be read by anyone responsible for choosing storage solutions
for their organizations or for making administrative personnel decisions in the data
center.
Methodology Overview
Edison performed the series of tasks described in this white paper on storage systems
from IBM and EMC. The methodology and specifications for the hardware and software
evaluated are listed in the section of this paper entitled “Methodology for This Study.”
NOTE The two products compared in this study are both unified storage systems.
However, this study specifically evaluated only their block-based storage features.
Contents of this White Paper
Executive Summary – a summary of the context for and results of Edison’s research.
Storage Management Costs in the Enterprise – overview of the factors affecting
storage management costs and a discussion of the products tested in this study.
Overview of the Products – description of the products evaluated in this study and
the management software user interface for each.
Results Summary – summary of the overall results of the evaluation.
Results Details – discussion of the results for each task category evaluated.
Methodology for This Study – overview of the methodology Edison used in
performing the hands-on research.
Conclusions – summary of the results of Edison’s research.
Appendices – a more detailed discussion of the evaluation methodology and a
terminology glossary.
Edison: Comparing Management Costs for IBM Storwize V7000 and EMC VNX5500 Page 5
Storage Management Costs in the Data Center
Edison Group has developed the Competitive Management Cost Study (CMCS)
methodology for applying hands-on research comparing administrative consoles of
storage systems to determine how their relative ease of use affects the ownership costs of
each system. Edison’s CMCS analyses have been used to evaluate administrative
consoles for mid-range storage systems from major vendors such as HP, NetApp, EMC,
and now from IBM.
New trends and developments, such as uncontrolled capacity growth, virtualization,
and facility costs, affect acquisition decisions for storage systems. The exponential
growth in capacity requirements is widely acknowledged. Storage virtualization, too,
has become accepted as the standard approach for storage systems of all sizes, from
Data Robotics, Inc.'s Drobo SOHO arrays to the largest enterprise systems from IBM,
EMC, HP, and NetApp. Similarly, server virtualization is being widely deployed:
according to executives at VMware, the largest vendor of server virtualization on the
x86/x64 platform, there are now more virtual servers running under VMware than
physical servers.
As for facilities costs, even with increased drive capacities and storage consolidation via
virtualization, growing capacity requirements still translate into growing expenses.
The inexorable growth of application demand and data retention requirements is
driving the need to control the cost of managing storage systems, by far the most
significant OPEX cost-control lever that exists. In the years since Edison developed our
first CMCS report on managing mid-range systems, many storage vendors have made
strides in addressing the costs of management complexity by improving their
management software. This report covers a comparison between the currently available
IBM Storwize V7000 storage system and EMC VNX.
Edison: Comparing Management Costs for IBM Storwize V7000 and EMC VNX5500 Page 6
Spotlight on Automated Tiering
This paper focuses on time and complexity
savings through the management software
of the products. Worth noting, though, is
that IBM Storwize V7000 also has features,
including automatic tiering, virtualized
pooling and virtualization of external
storage systems, which can make the most
effective use of storage resources, enhancing
performance and reducing OPEX. IBM
Storwize V7000 allows any combination of
supported heterogeneous storage devices to
be enlisted in a single virtualized pool that
can be accessed regardless of underlying
hardware resources.
Specific types of data can also be assigned
to appropriate types of storage. For
instance, data for applications that require
extremely fast response times can be
assigned to solid-state drives (SSDs), while
data requiring less demanding access
speeds can be stored on less costly
traditional spinning disk drives. Using IBM
System Storage Easy Tier technology,
frequently-used data can be automatically
moved to high performance SSDs based on
ongoing performance monitoring. This
approach enables an organization to benefit
from SSD technology at lower cost than an
all-SSD solution, yet without requiring
administrators to create and manage
storage tier policies. A similar technology
from EMC (FAST) is not nearly as granular
as EasyTier and, therefore, not as efficient.
Overview of the Products
The products evaluated for this white paper represent the latest generation of mid-range
storage products, designed for medium-sized to enterprise businesses, from IBM and
EMC. Data centers frequently deploy Storage Area Network (SAN) storage systems for
applications requiring the highest levels
of performance, while separately
deploying Network Attached Storage
(NAS) for its ease of use and less
expensive networking. This approach
adds to complexity, introducing multiple
points of management and creating
islands of storage, which have adverse
impacts on efficiency.
Both products evaluated in this study are
designed to provide a single solution that
is more affordable and less complex to use
than higher-end storage. Powered by Intel
Xeon processors, both incorporate such
advanced technology as virtualized
storage, thin provisioning, and tiering to
help close the gap between exponential
data growth and IT storage budgets.
IBM Storwize V7000
Storwize V7000 combines hardware and
software components to help support
improved storage efficiency through a
single point of control. It is designed to
improve application availability and
resource utilization via a variety of
technologies including thin provisioning,
automated tiering, storage virtualization
(internally and externally), clustering,
replication, multi-protocol support, and a
robust, intuitive Graphical User Interface
(GUI).
Edison: Comparing Management Costs for IBM Storwize V7000 and EMC VNX5500 Page 7
The storage system is packaged in 2U rack-mountable enclosures that house up to 24
2.5-inch drives or up to 12 3.5-inch drives. Control enclosures contain drives, redundant
dual-active intelligent RAID controllers, dual power supplies, batteries, and cooling
components. Expansion enclosures contain drives, switches, power supplies, and
cooling components. Control enclosures can be clustered and up to nine expansion
enclosures can be attached to a control enclosure, supporting up to 240 drives.
Tasks related to out-of-the-box product installation and setup were not evaluated for
this study. However, the relative simplicity of the IBM Storwize V7000 initialization is
worth noting here. The IBM Storwize V7000 initiation employs a USB dongle: the
administrator sets the IP address, inserts the dongle, and initial discovery and
provisioning takes place, speeding deployment and reducing initial setup costs.
EMC VNX5500
EMC replaced its former CLARiiON and Celerra product lines with new models under
the VNX brand. These new storage systems combine many of the features of CLARiiON
and Celerra and include several hardware changes, including an update to the Intel
processor in the controller. In addition, EMC has joined the transition from 3.5-inch FC
drives to 2.5-inch SAS drives as the new standard for high performance enterprise-class
spinning disks. 3
The storage system is packaged in rack-mountable enclosures that house up to 25 2.5-
inch disk drives or SSDs, or up to 15 3.5-inch drives. Disk Processor Enclosures (DPEs)
contain drives, redundant dual-active intelligent RAID controllers, dual power supplies,
and dual cooling components. Disk Array Enclosures (DAEs) contain drives, switches,
power supplies, and cooling components. Up to nine DAEs can be attached to a DPE,
supporting up to 250 drives.
Overview of the Management Consoles
Edison Group developed the CMCS analysis with the premise that an efficiently
designed, intuitive GUI can reduce the time administrators spend managing storage, as
well as the time spent training and refreshing staff. It can also serve to greatly reduce the
number and length of calls to support administrative issues.
3 EMC VNX Series also supports optional SSD and associated data tiering in conjunction with the
addition of EMC FAST Suite software.
Edison: Comparing Management Costs for IBM Storwize V7000 and EMC VNX5500 Page 8
IBM Storwize V7000 Management Interface
A browser-based GUI, the IBM Storwize V7000 management interface is intuitive and
easy to navigate. The home page offers four optional views. The default view is the
Getting Started screen (Figure 1), a robust graphic interface through which you can view
the configuration status and access the means for performing specific tasks.
Figure 1: IBM V7000 Getting Started Screen
The Getting Started screen presents an object-oriented view. Click on any onscreen
object to go to management operations and/or stats displays for those items. The screen
shown here provides an excellent graphical flow chart of the system components and
the steps required to provision storage-to-host systems. This view provides an easy way
to confirm physical system resources and components, as well as a gateway to
configuring more advanced system features. The Getting Started view additionally
provides e-Learning and Information Center links that can provide detailed information
on each component in the storage provisioning process.
The Storwize V7000 management interface provides an object-oriented view of the
system components organized in column format on the left side of each display, as
shown in Figure 2 (below). This allows for easy scrolling from component to component.
Edison: Comparing Management Costs for IBM Storwize V7000 and EMC VNX5500 Page 9
Positioning the cursor over an individual object will provide drill-down options of
available administration tasks for the component depicted by the object.
Figure 2: IBM Storwize Volumes Status & Management View
In this view, the middle of the screen displays system status information for volumes
(also commonly referred to as LUNs). The bar graph to the left indicates system capacity
(used capacity in blue and total system capacity in black), and a component view is in
the middle of the display. Position the cursor over each object to display detailed system
information.
Detailed information on the drives in each enclosure can be displayed by clicking on a
disk shelf in the graphic. Clicking the link below the display presents a table of system
statistics.
Volumes in the Storwize V7000 system are virtual containers. They are abstracted from
physical disk drives (internal to the system or on external virtualized systems) via
managed disks and pools and then presented to host servers. The “Volume by Pool”
view (shown in Figure 3, below) allows the administrator to see detailed information for
each Storwize V7000 volume, including its pool association.
Edison: Comparing Management Costs for IBM Storwize V7000 and EMC VNX5500 Page 10
Figure 3: IBM Storwize Volume by Pool View
The display shown in Figure 4 (below) shows an example of the interface used in
creating a Volume, which provides options between preset defaults or the flexibility for
customized volumes with the Advanced tab.
Figure 4: IBM Storwize Creating a Thin-Provisioned Volume
Edison: Comparing Management Costs for IBM Storwize V7000 and EMC VNX5500 Page 11
EMC Unisphere
The management console for the EMC VNX Series, EMC Unisphere, runs solely on a
Windows server and allows for the monitoring and management of multiple EMC
CLARiiON, Celera, and VNX storage systems from a single console. In addition, EMC
Unisphere presents an attractive and informative monitoring dashboard as the default
view. The screenshot in 5 (below) shows a dashboard view.4
Figure 5: EMC Unisphere Dashboard
Dashboards provide a status overview for each function on the managed storage
systems. Unlike the IBM Storwize V7000 management interface, the Unisphere
dashboard offers considerable flexibility in the customization of its displays. A single
screen for at-a-glance management and reporting, the Unisphere dashboard gives you
instant and actionable knowledge about status and events across the entire storage
environment. Properly set up so that all systems have the same username and password,
Unisphere’s single sign-on can automatically discover all supported EMC installations in
the environment, including VNX, CLARiiON, Celerra, and EMC RecoverPoint SE.
4Our test environment contained one new storage system, so the amount of information
presented is limited to that system.
Edison: Comparing Management Costs for IBM Storwize V7000 and EMC VNX5500 Page 12
Unisphere includes a self-service support ecosystem that is accessible with one-click,
task-based navigation, and controls for intuitive, application context-based
management. It provides customizable dashboard views, graphics, and data tables that
present key information in the context of how you manage storage.
The display shown in Figure 6 (below) shows an example of the interface used in
creating a LUN.
Figure 6: EMC Unisphere - Create LUN Interface
Edison: Comparing Management Costs for IBM Storwize V7000 and EMC VNX5500 Page 13
Results Summary
The results of Edison’s testing (Table 1, below) show that IBM Storwize V7000
demonstrates significant advantages over EMC VNX5500 in the area of management
ease and, therefore, in administrative costs.5
Our objective findings show that, overall, managing an IBM Storwize V7000 system with
its management interface software is 47 percent less time-consuming and 31 percent less
complex over a set of common tasks than managing an EMC VNX system using
Unisphere software.
Table 1: IBM Storwize V7000 CMCS Summary of Results
IBM Storwize V7000 EMC VNX 5500
Task Time Steps Time Steps
Provisioning
Test Results for Task Category 176 8 400 14
IBM Advantage (EMC-IBM) 224 6
IBM Advantage %
(EMC-IBM/ABS(EMC)) 56% 43%
Workday Savings (IBM Advantage *
Weighting Factor) 8%
Data Protection Replication
Test Results for Task Category 103 9 301 15
IBM Advantage (EMC-IBM) 198 6
IBM Advantage %
(EMC-IBM/ABS(EMC)) 66% 40%
Workday Savings (IBM Advantage *
Weighting Factor) 9%
Maintenance and Configuration
Test Results for Task Category 172 12 159 12
IBM Advantage (EMC-IBM) -13 0
5 The Microsoft Excel formulas used in the calculations throughout this document are shown in
parentheses next to each title.
Edison: Comparing Management Costs for IBM Storwize V7000 and EMC VNX5500 Page 14
IBM Storwize V7000 EMC VNX 5500
Task Time Steps Time Steps
IBM Advantage %
(EMC-IBM/ABS(EMC)) -8% 0%
Workday Savings (IBM Advantage *
Weighting Factor) -1%
Monitoring
Test Results for Task Category 55 2 90 4
IBM Advantage (EMC-IBM) 35 2
IBM Advantage %
(EMC-IBM/ABS(EMC)) 39% 50%
Workday Savings (IBM Advantage *
Weighting Factor) 5%
Totals
Test Results Totals 506 31 950 45
Total Time Savings: IBM Advantage
(EMC-IBM) 444 14
IBM Advantage %
(EMC-IBM/ABS(EMC)) 47% 31%
Average Workday Savings (IBM
Advantage % * Total Factors tested) 34%
$ Savings6 $25,686
For most IT executives, the best way to appreciate the importance of management cost
savings is by examining the findings in the context of OPEX cost savings.
The Total Time Savings in the table above is simply a sum of the savings for the tasks
evaluated. In general, Edison believes that these raw numbers do not accurately reflect
the actual workloads storage administrators’ experience (as reflected in the Average
Workday Savings), because they do not include all the tasks they perform during the
day. In order to address this, Edison developed a set of workload weighting factors that
could be applied to our testing; Edison surveyed storage administrators using storage
systems from several vendors, in organizations of all sizes.
6 Average Workday Savings x Salary derived from Table 3: Average Storage Administrator Salaries
(page 16). Results are rounded to whole dollar.
Edison: Comparing Management Costs for IBM Storwize V7000 and EMC VNX5500 Page 15
The Edison white paper, Comparative Management Cost Survey: Workload Weighting
for Mid-Range Storage Array Administrators, describes the research leading to the
identification of the weighting factors. It can be found in the Published Reports Library
on the Edison web site at http://www.theedison.com.
The factors included in this study are presented in Table 2 (below). Only those
appearing in shaded rows (i.e., 74 percent of the total workload weighting factors
identified) were factored into the evaluation for the current study.
Table 2: Storage Administrator Workload Weighting Factors
Weighting Factors 7
Provisioning 14%
Data Protection 16%
Maintenance 27%
Problem Solving 17%
Application Specific 13%
Overhead 12%
Total factors for tests
performed in this study 74%
Average Storage Admin Pay $76,333
As seen in the Average Workday Savings total in Table 1, when these weighting factors
are applied to the raw time-savings test results, IBM Storwize V7000 demonstrated a 34
percent advantage over the EMC VNX5500 system. This is examined more granularly in
the Results Details sections of this white paper.
Comparative Management Cost Savings
The Edison CMCS methodology assigns a complexity metric to task categories, as well
as measuring and comparing the time required to perform different tasks. In most real-
world business environments, management costs far outweigh licensing and vendor-
charged support costs throughout the life of the product. With this in mind, we
estimated the annual cost a business might expect save on storage administrator time
resulting from one product being easier to administer and operate than the other.
7 The weighting factors do not add up to 100 percent due to rounding.
Edison: Comparing Management Costs for IBM Storwize V7000 and EMC VNX5500 Page 16
In order to compute cost savings, Edison used Storage Administrator salary figures
gathered from a query of salaries made at Simplyhired.com8. Edison searched for the
salaries in seven metropolitan areas of various sizes and cost-of-living. Though different
choices would affect the results, Edison believes the derived average salary is
reasonable.
Table 3: Average Storage Administrator Salaries
Storage Administrator Salaries
New York City $87,000.00
Atlanta, GA $ 73,000.00
Houston, TX $ 71,000.00
St. Louis, MO $ 69,000.00
Chicago, Il $ 76,000.00
Phoenix, AZ $ 66,000.00
Los Angeles, CA $ 69,000.00
San Francisco, CA $ 93,000.00
Seattle, WA $ 83,000.00
Average $ 76,333.00
The average of the results of this search (Table 3, above), when multiplied by the
weighted time savings, show cost savings for IBM Storwize V7000 system versus EMC
VNX5500 system:
Median Storage Administrator Salary * (Storage Administrator Time Savings) =
$76,333 * 34% = $25,686
By substituting its own costs, an organization can determine its potential savings.
Edison recognizes that these savings are not going to be realized directly. Instead, they
need to be interpreted within the context of overall storage administrator duties and
storage group or IT budgets. Within this framework, time savings of over 34 percent can
translate to reducing the need for new hires when additional storage systems are
acquired, or to enabling a better allocation of resources to mission-critical tasks.
It is not practical to attach direct financial costs to complexity. However, it should be
apparent that more complex management tools require more user training, can cause
user error simply due to that complexity, and can otherwise affect productivity.
8 This and similar queries can be performed at http://www.simplyhired.com/a/salary/home
Edison: Comparing Management Costs for IBM Storwize V7000 and EMC VNX5500 Page 17
These objective differences do not tell the whole story. As is seen elsewhere in this white
paper, in most respects performing management tasks with the IBM Storwize V7000
management interface generally provides a better user experience than does EMC
Unisphere. Fewer steps and a more intuitive interface reduce the odds of user error in
execution.
Edison: Comparing Management Costs for IBM Storwize V7000 and EMC VNX5500 Page 18
Results Details
Edison compared the performance of four categories of tasks: Provisioning, Data
Protection, Maintenance, and Monitoring. Since the architecture and management
approaches of the two vendors differ, not all the tasks that comprise a tested category
could be compared. Where no equivalent function or task existed for both platforms, the
time and complexity rating results were not included in the summarized results.
Similarly, some tasks, such as replacing a disk, could not be performed for all of the
platforms as the test systems lacked sufficient additional disks.
The following sections each contain a description of the task categories, a summary of
test results for that category, a listing of the tasks performed and compared, and a
subjective appraisal of the user experience.
Provisioning
For purposes of this study, provisioning covers tasks performed after the storage system
has been installed and initialized. Installation-related tasks were not included for two
main reasons: first, a system is only installed once; second, for many organizations,
installation is performed by vendor technicians. There are organizations where storage
systems are being added to the data center daily but, in such cases, the installation teams
are generally vendor-provided technicians or staff dedicated to that task.
The tasks evaluated here include those related to preparing connectivity and the storage
devices for use by hosts. The following table (Table 4: Provisioning Tasks Comparison,
page 20) shows the specific provisioning tasks, using nomenclature for each vendor that
Edison evaluated.
Provisioning Tasks and Summary
The tasks evaluated for the respective systems were as follows:
IBM Storwize V7000 System
Configure Physical Storage (Internal Storage - Default RAID 5) — Internal storage
is the RAID-protected storage that is directly attached to the Storwize V7000 system.
The Storwize V7000 system automatically detects the drives that are attached to it.
These are configured into RAID arrays, presented as MDisks, which can be added to
storage pools in the same way as MDisks that are discovered when external storage
systems are added.
Edison: Comparing Management Costs for IBM Storwize V7000 and EMC VNX5500 Page 19
Create New Volume (LUN) — A volume is a logical disk that the system presents to
the hosts. Volumes can be Generic, Thin, Mirrored, or Thin Mirrored.
Add/Create Hosts — A host system is a computer that is connected to Storwize
V7000 through a Fibre Channel interface (IP network is also an option).
Assign/Map Volumes to Hosts — Host mapping is the process of controlling which
hosts have access to specific volumes within the system.
Search for Volumes —Previously configured hosts can be mapped to previously
configured volumes that are found.
EMC VNX5500 System
Create Storage Pools (Default RAID 5) – A storage pool is a set of disks all with the
same redundancy (RAID 5, RAID 6, or RAID 1/0), on which you create one or more
thin or non-thin LUNs.
Create LUN – (RAID 5 default, thin or non-thin).
Create/Add Hosts.
Creating Storage Groups – A storage group is a logical grouping of LUNs and hosts.
that enables managing both as a single unit.
Host Assignment to Storage Group.
LUN Assignment to Storage Group.
Search for LUNs.
The Summary of Results for Provisioning in Table 4 (below) shows that, for the
compared tasks, the IBM Storwize V7000 system was 56 percent less time-consuming
and 43 percent less complex to manage than the EMC VNX5500.
Table 4: Provisioning Summary of Results
IBM Storwize V7000 EMC VNX 5500
Task Time Steps Time Steps
Provisioning
Test Results for Task Category 176 8 400 14
IBM Advantage (EMC - IBM) 224 6
IBM Advantage %
(EMC-IBM/ABS(EMC)) 56% 43%
Workday Savings
(Difference* Weighting Factor) 8%
Edison: Comparing Management Costs for IBM Storwize V7000 and EMC VNX5500 Page 20
When the weighting factor is applied, the advantages are smaller, but can be
cumulatively significant when these activities are urgent.
The two charts below illustrate the differences in provisioning time and complexity for
the two platforms.
Figure 7: Provisioning: Time and Complexity Comparisons
Edison: Comparing Management Costs for IBM Storwize V7000 and EMC VNX5500 Page 21
Data Protection
Without good data protection capabilities, there is almost no reason to invest in a
storage system. Data protection includes such features as multiple controllers, multiple
I/O paths, remote replication, and the creation of snapshots and copies. Multiple
controllers and I/O paths are dependent upon the physical attributes of the appliance
and are generally configured as part of installation. This study does not include an
evaluation of the management of the physical controllers and I/O paths. Remote
replication was not tested because the Edison lab only had one system from each
vendor. That leaves the creation of copies and snapshots. 9
A copy 10 is defined essentially the same way on either platform — an exact replica of
existing data on the system managed in the same manner as the source data. Copies can
be used as a backup, especially when replicated to a second local or remote storage
system. This approach, typically used to enable high availability, usually takes the form
of what EMC terms a mirror and IBM calls a mirrored pair, meaning that the data in
each copy is regularly updated and synchronized through replication. Copies can be
made to retain a relationship with the original data, or not. Copies are also often used in
development environments where it is desirable for developers to work with real data,
but where using live data would be too risky to allow.
A snapshot creates a point-in-time view of the original data. The snapshot is not
intended to be an independent copy but is used to maintain a view of the original data at
the time the snapshot is created. Therefore, the snapshot holds only the data from
regions of the original volume that have changed subsequent to the creation of the
snapshot (starting with no data at all). Since the snapshot uses thin provisioning, only
the capacity required for the changes is used. Compared to full copies, snapshots require
much less additional storage space on an array — typically 10 to 20 percent of the
original size, rather than the 100 percent capacity required by a copy.
On the EMC product, snapshots are created at the LUN or Vdisk level. For EMC, each
LUN can have its own snapshot policies, easily matching the business needs.
9 For in-depth descriptions and explanations of these functionalities in IBM Storwize V7000, documentation
can be accessed at:
http://publib.boulder.ibm.com/infocenter/storwize/ic/index.jsp?topic=%2Fcom.ibm.storwize.V7000.doc%2F
mlt_relatedinfo_224agr.html 10 Often referred to as a clone; though to avoid confusion between product nomenclature, “copy” is used
except in explicitly defined instances.
Edison: Comparing Management Costs for IBM Storwize V7000 and EMC VNX5500 Page 22
On the IBM product, snapshots are accomplished using a FlashCopy snapshot preset
function that creates a point-in-time view of the production data.
Data Protection Tasks and Summary
The tasks evaluated for the respective systems were as follows:
IBM Storwize V7000 System
Create Snapshot
Create Copy
Flash Copy Mappings – equivalent to Snap Mirror – maps snapshot to source for
updating
Start Snap
Restore Snap/Copy
EMC VNX 5500 Systems
Create Reserved LUN Pool – to hold snapshots
Creating a Snapshot (SnapView) – sets the parameters for the snapshot
Start Snapshot Session – this creates the snapshot
Add a Snapshot to Storage Group
Activate and Deactivate Snapshots – making it available (or unavailable) to a host (in
a Storage Group)
Restoring Snapshot Copies
Configure Clone (Copy) Settings
Creating Snap Clone (Copy)/Mirror
Consistency groups are a notable time-saver in the typical scenario, where applications
are associated with multiple LUNs/volumes. Enabling a single, consistent point-in-time
copy across multiple volumes, consistency groups are important in scenarios such as a
database environment, where obtaining a consistent copy would require a temporary
suspension of database operations. Consistency groups allow administrators to group
multiple volumes, after which they can create a copy of, or restore, particular groups
instead of individual volumes. For example, standard practice with SQL Server would
be to have a volume in the Storwize V7000 storage system for data, and logs stored on
another volume in order to keep them (and possibly configure them) separately. You can
Edison: Comparing Management Costs for IBM Storwize V7000 and EMC VNX5500 Page 23
combine them into a “SQL Server Consistency Group” and snapshot or copy them as a
single entity for such purposes as recovery or development.
As can be seen in Table 5 below, when the IBM system is compared to the EMC system,
it is 66 percent less time-consuming and 40 percent less complex to manage.
Table 5: Data Protection Summary of Results
IBM Storwize V7000 EMC VNX 5500
Task Time Steps Time Steps
Data Protection Replication
Test Results for Task Category 103 9 301 15
IBM Advantage (IBM - EMC) 198 6
IBM Advantage %
(EMC-IBM/ABS(EMC)) 66% 40%
Workday Savings
(Difference* Weighting Factor) 9%
The two charts below show the differences more dramatically by providing a visual
indication of differences in data protection time and complexity for the two platforms.
Edison: Comparing Management Costs for IBM Storwize V7000 and EMC VNX5500 Page 24
Figure 8: Data Protection: Time and Complexity Comparison
Maintenance and Configuration Changes
Maintaining a storage system includes a wide range of activities, including software
updates, replacement of failed drives, and so forth. Configuration changes include
additional capacity realized by adding drive shelves and drives, changing usage
configurations, and the deletion of snapshots and copies for which there is no further
use.
The Maintenance and Configuration Changes tasks evaluated in this study consist of
such activities as deleting outdated snapshots, managing and expanding LUNs,
destroying inactive LUNs, and reconfiguring or decommissioning storage pools or
aggregates. Other tasks that fit under the topic but that were not evaluated include
removing and replacing failed drives, adding additional drives, and so forth.
Maintenance and Configuration Changes Tasks and Summary
The tasks evaluated for the respective systems were as follows:
Edison: Comparing Management Costs for IBM Storwize V7000 and EMC VNX5500 Page 25
IBM Storwize V7000 System
Expand Storage Pool
Delete Storage Pool
Expand Volumes
Delete Volumes
Delete Snapshots
Delete Copies
Search Volumes
Delete Host
EMC VNX5500 System
Expand Storage Pool
Expand LUNs
Destroying LUNs
Destroying RAID Groups/Storage Pool
Destroying/Deactivating Snapshots
Destroying Clones (Copies)
Deleting Host
Performing tasks may require additional prior tasks. For example, destroying a clone
(copy) that is attached to a host requires that it be detached from the host or taken offline
before it can be destroyed. The number of different possible scenarios would, if
included, add unnecessary complexity to this analysis.
The results in Table 6 (below) show that performing these tasks with Unisphere is 8
percent faster than performing the equivalent tasks with the IBM Storwize V7000
management interface. A comparison of the individual tasks reveals that the time
difference was due to two factors. First, an additional task, Search LUNS/Volumes was
performed on the V7000 that was not tested on the VNX – this added 12 seconds to the
total. Second, the time required to expand the storage pool was longer on Storwize
V7000 than on the VNX. The resulting 8 percent advantage for VNX is significant, in
itself, but when weighting is applied, the resulting 1 percent difference is insignificant.
Edison: Comparing Management Costs for IBM Storwize V7000 and EMC VNX5500 Page 26
No appreciable difference in complexity was found between the two management
interfaces for these tasks.
Table 6: Maintenance and Configuration Changes: Summary of Results
IBM Storwize V7000 EMC VNX 5500
Task Time Steps Time Steps
Maintenance and Configuration
Test Results for Task Category 172 12 159 12
IBM Advantage (IBM - EMC) -13 0
IBM Advantage %
(EMC-IBM/ABS(EMC)) -8% 0%
Workday Savings
(Difference* Weighting Factor) -1%
The following two charts provide a graphic illustration of the performance differences.
Edison: Comparing Management Costs for IBM Storwize V7000 and EMC VNX5500 Page 27
Figure 9: Maintenance and Configuration Changes Comparison
Monitoring
During the interviews Edison conducted when developing the workload weighting
factors, many of the respondents mentioned that their most important activity was
monitoring system status. By its nature, monitoring does not require significant effort,
but properly configuring monitoring tools both enables timely preventive maintenance
and simplifies troubleshooting. Performing troubleshooting tasks most often occur
outside of the management interfaces, so were not included in this study.
For this study, Edison only compared the management tools provided in the two
management consoles, IBM Storwize V7000 and Unisphere. Monitoring tools that
required the use of external software were not included. In addition, since monitoring is
a passive process by definition, we did not evaluate the use of the monitoring tools
themselves.
Therefore, we compared only the configuration of monitoring on the two systems. The
tasks evaluated for the respective systems were as follows:
Edison: Comparing Management Costs for IBM Storwize V7000 and EMC VNX5500 Page 28
IBM Storwize V7000 System
Configure Event Notifications – E-mail
Configuring Event Monitoring – SNMP/Syslog
Remote Support/Dial Home
EMC VNX5500 System
Configuring EMC Event Monitoring – E-mail
Configuring EMC Event Monitoring – SNMP
Configuring Host Notification
Configuring Remote Support
It is important to note that though Edison performed all the tasks for both platforms, not
all of the tasks were performed separately on each. For example, with Unisphere, all of
the monitoring configuration tasks are performed without using additional utilities.
Table 7: Monitoring: Summary of Results
IBM Storwize V7000 EMC VNX 5500
Task Time Steps Time Steps
Monitoring
Test Results for Task Category 55 2 90 4
IBM Advantage (IBM - EMC) 35 2
IBM Advantage %
(IBM-EMC/ABS(IBM)) 39% 50%
Workday Savings
(Difference* Weighting Factor) 5%
The effect of task consolidation is evident in the results in Table 7 (above). Even though
there is only one interface required for configuring monitoring on VNX versus two on
V7000 (there is a separate interface for configuring remote support), there were twice as
many steps required to perform the same activity on VNX and the time difference, near
40 percent, is quite large.
Edison: Comparing Management Costs for IBM Storwize V7000 and EMC VNX5500 Page 29
Figure 8: Monitoring Comparison
Edison: Comparing Management Costs for IBM Storwize V7000 and EMC VNX5500 Page 30
Though troubleshooting tasks were not evaluated for this study, the IBM Storwize
V7000 management interface has a wizard-based troubleshooting aid, Recommended
Actions, which deserves mention, since it can reduce demands on an administrator’s
time. Clicking Recommended Actions in the Troubleshooting popup brings up a
context-sensitive display appropriate to the detected problem. Selecting an error code or
message and clicking on “Run the Fix Procedure” will bring you though the steps
involved in addressing the problem, as shown in the example below (Figure 10).
Figure 10: IBM Storwize V7000 Recommended Actions Display
The Recommended Action feature can save administrators from having to search
through the Help screen knowledge base to determine how to diagnose and remedy the
problem.
Edison: Comparing Management Costs for IBM Storwize V7000 and EMC VNX5500 Page 31
Methodology for This Study
Edison deployed storage systems from IBM and EMC in a lab within its New York City
facility, and then performed a series of management tasks, capturing the steps and time
required using the Edison Comparative Management Costs Study methodology. Details
about the methodology, as well as the lab configuration and the testing process, are
described below.
CMCS Methodology
The CMCS methodology was created by Edison to be able to objectively compare the
manageability ease-of-use for enterprise technology products. Edison devised the
methodology to provide an objective metric for comparing Information Technology
management platforms. More subjective metrics, such as those derived from interviews
with groups of testers in typical user-experience testing, are excellent for understanding
the testers’ preferences at the time of testing, but results vary significantly for different
groups of testers and test conditions.
Objective metrics based on mouse clicks cannot adequately address issues such as the
difference between Wizard-based versus non-Wizard based interfaces. The Edison
methodology attempts to address these concerns by establishing a set of rules that can
account for complexity and different interface design philosophies. A full description of
the methodology can be found in the appendix of this report.
Laboratory Configuration
Edison's test lab was configured with systems from IBM and EMC. On the following
page, Table 8 lists the storage system models, hardware features, and the licensed
software installed in the lab.
Edison: Comparing Management Costs for IBM Storwize V7000 and EMC VNX5500 Page 32
Table 8: Lab Configuration
VNX5500
Hardware
Model EMC VNX5500
Storage Processor Dual Processor (SPA & SPB)
Memory Per Processor 12288 MB
Revision/Flare Code 5.31.0.5.502
Storage
Disk Array Enclosure 0 – 24 Disks (Includes two Hot spares)
1 – 24 Disks (Includes two Hot spares)
Disk Type 300 GB SAS
RAID Configuration RAID 5
Storage Capacity Physical Capacity 14.4TB Raw, minus EMC VNX OS
Vault space
Licensed Software
EMC Unisphere File & Block (Navisphere license included.
Unisphere replaces Navisphere at installation).
SnapView, SAN Copy
IBM Storwize V7000
Hardware
Model Storwize V7000
Revision 6.2.0.3
Memory per Processor 8000 MB
Storage
Drive Enclosure 1 – 24 Disks
2 – 24 Disks
Disk Type 300 GB 10K SAS
Storage Physical Capacity 14.4 TB Raw
Licensed Software
Storwize Management Software
Copy Services – Flash Copy & Remote Copy
Edison: Comparing Management Costs for IBM Storwize V7000 and EMC VNX5500 Page 33
Test Procedures
This study focuses on regularly performed administrator tasks. Edison divided the tasks
into categories that relate to the tasks typically performed by storage administrators on a
daily basis: 11
Provisioning – Provisioning includes all the tasks or operations performed after
installation in order to attach an array to servers and store data. These include global
tasks such as creating a storage pool, configuring ports for connectivity to hosts, and
the creation LUNs or volumes so the array can actually be put to use.12
Data Protection – Data protection covers such features as the creation of snapshots
and copies.
Maintenance and Configuration Changes – Maintenance and Configuration
Changes include performing maintenance tasks such as adding additional capacity,
cleaning up unneeded snapshots, copies, and so forth.11
Monitoring and Troubleshooting – Monitoring an array consists of identifying
performance and operational parameters that affect uptime and performance, setting
alerts, and generating reports on status and system condition. Troubleshooting
consists of identifying the causes of issues identified through monitoring, or from
other sources, such as server administrators or end users concerned about
performance or data availability. Only enabling and configuration of monitoring
were evaluated in this study.
Overhead or Other – These tasks include such tasks as budget or planning meetings,
training, and other activities not directly related to any specific storage array. These
activities were not evaluated in this study.
Edison identified tasks under each category and matched them between the platforms
compared in this study. Since the vendors use either different nomenclature for the same
feature or the same nomenclature for different features, this was a very important first
step.12
Administrators rarely perform specific tasks in isolation. Often, the administrator has a
goal that requires the performance of a combination of several tasks or operations. To
11 The tasks listed for the categories are illustrative, not inclusive. Not all of the tasks listed were
evaluated nor are all possible tasks for a category listed. In addition, these categories are not
exclusive: tasks listed for one category may be justifiably perceived as belonging to a different
category. 12 See the appendix for a table comparing the equivalent nomenclature for the features and
functionality used by each of the vendors.
Edison: Comparing Management Costs for IBM Storwize V7000 and EMC VNX5500 Page 34
emulate this approach, Edison further categorized the task list to reflect a goal-oriented
approach. This also simplified comparisons where the architectural differences between
the two platforms would make task-to-task comparisons difficult or even impossible.
Table 9 (below) shows the list of tasks and goals, organized by category.
Table 9: Task Categories
Provisioning
Baseline Provisioning Tasks that need to be performed prior to creating usable storage
on any storage system.
Preparing Storage This series of tasks includes the creation of a storage pool from
the drives in the system.
Preparing
Connectivity
For this study, this series of tasks includes all the operations
required for setting up access to FC Hosts on the system.
Configuration of other network protocols was not evaluated in
this study.
Configuring Usable
Storage
This category includes the creation of storage objects that can be
attached to a host or server.
Data Protection
Creating Snapshots These tasks include the creation and scheduling of snapshots.
Creating Clones
(Copies) These tasks include the creation of clones.
Replication These are tasks related to replicating data onto remote storage
systems. Replication tasks were not performed during this study.
Maintenance and Configuration Changes
Removal of Unused
Storage Objects
This includes the deletion of old snapshots or clones, deletion of
LUNs, etc.
Monitoring and Troubleshooting
Monitoring and
Troubleshooting
This includes the performance of a series of tasks related to the
identification of problems on the systems. For this study, the
comparison focuses on the configuration of monitoring tools.
GUI vs. CLI
Edison believes that well designed GUIs can greatly improve the quality of system
management, compared to the exclusive use of a command line interface (CLI) or
scripting. This is especially true for the less skilled staff usually tasked with day-to-day
management.
Edison: Comparing Management Costs for IBM Storwize V7000 and EMC VNX5500 Page 35
Getting the Best of Both Approaches
As stated in the accompanying subsection, the
ideal GUI is one that generates CLI commands
to reflect the actions implemented using the
GUI. This feature is part of the IBM Storwize
V7000 management interface. It is a useful
way for administrators to learn the various
CLI commands. Additionally, the commands
generated by GUI actions may be copied and
pasted into a text editor in order to create
scripts that can then be executed by the
system. In this manner, an administrator can
programmatically automate frequently used
actions. Doing so could result in still further
reducing the time and steps involved in using
the IBM Storwize V7000 system over other
storage systems.
An example of this can be seen in creating
LUNs. In EMC Unisphere the Create LUN
dialog box (Figure 5, page 10), creating
multiple LUNs is simply a matter of entering
the number to be created in the “Number of
LUNs to Create” field. The IBM Storwize
V7000 management interface lacks an
equivalent field; though multiple volumes can
be created within the “New Volume” dialog
box, each instance needs to be added
manually. However, if creating volumes is
done on a frequent basis, a script can be
created using CLI commands generated by the
GUI, which can be used to create a specific
number of volumes with a single action.
Edison does not oppose the use of the CLI or scripts, but we believe that for the majority
of day-to-day tasks, a GUI can lower training and task-oriented support costs and
prevent operator error (both significant factors in administrative efficiency) and thus,
cost. In fact, a good GUI should streamline the use of scripts by providing an interface
for running and creating scripts through learning or similar capabilities. By enabling the
use of scripts for the performance of repetitive tasks while providing access through a
GUI, the best features of both approaches can be utilized.
Dick Benton, principle consultant at
GlassHouse Technologies, Inc., wrote an
article on storage staffing published by
SearchStorage. The theme of the article is
that a traditional measure of storage
administrator staffing needs — Terabytes
per Full-Time Employee — is almost
meaningless. This is because the metric can
only be calculated within the context of each
individual organization. As a practical
matter, TB/FTE can only be used after
acquisition and implementation, and then
only for analysis of staffing requirements for
future expansion of the existing
infrastructure. Changing the infrastructure
to a different platform changes the basis for
TB/FTE calculations.
The article lists three things to consider
when calculating storage management
staffing requirements. The first factor is
called “technology factors”, which are the
technologies (hardware and software) that
require significant training or experience for
use. The other two factors, “transaction
factors” (the day-to-day tasks performed by
storage administrators) and “complexity
factors” (“factors that impact a storage
administrator's need for skills and the time
needed to execute a task”) have a major
influence on the technology factor. The
easier a technology is to use, the less training or experience is required for its use. Edison
employs these same criteria in comparing storage administrator costs in this study.
Edison: Comparing Management Costs for IBM Storwize V7000 and EMC VNX5500 Page 36
Other Considerations
As mentioned above, this study only considers the effect of greater administrative
efficiency on ownership costs. Other factors, such as acquisition costs, space and power
utilization, third-party installation, decommissioning, and so forth are not included.
There is one other ownership cost factor that is not being directly analyzed but which
has a bearing on this study: the importance and nature of planning in implementing
complex IT infrastructures.
Planning for a SAN implementation requires an analysis not only of how much storage
is required (including projected expansion), but also the nature of what is being stored.
Such considerations include the existence of Microsoft Exchange, SQL Server, or Oracle
databases, how much capacity they require, and what data protection policies are
needed for operational and regulatory reasons. At a minimum, SAN planning requires
the identification of the hosts to be attached to the system, operating systems and
application data to be stored, and any data retention and protection policies in place.
Installing any of the systems Edison evaluated requires these minimum planning steps.
In the modern organization, there is one constant for storage utilization: the storage
capacity required, and the hosts and applications to which it is attached, will change
rapidly and often in unanticipated ways. If a storage system offers insufficient flexibility
to accommodate the rapidly changing environment into which it is placed, the costs of
administration can grow very quickly. A system that requires adherence to an overly
structured planning process and storage schema can prove very difficult to adapt to
changing circumstances. A highly flexible system will enable rapid IT responsiveness to
business changes and lower the costs accrued from those changes.
How to Use These Results
White papers such as this one are intended to help readers make product acquisition
decisions. For midmarket storage arrays, the purchase decision must include many
factors. Mid-size organizations often have relatively smaller IT organizations, with
administrators wearing many hats. The more efficient the administrator’s toolset, the
more productive the administrative staff can be.
When reviewing these results, consider the organization’s file storage and application
integration requirements. Review staffing policies as well, including training programs
and other factors. Also, evaluate the skill levels of existing staff. If the team has great
skills and deep knowledge of storage management issues, the choice of storage system
management tools may seem moot; but a more efficient platform can enable teams to
make better use of their time.
Edison: Comparing Management Costs for IBM Storwize V7000 and EMC VNX5500 Page 37
Conclusions
The inevitable increase in storage capacity requirements, along with other factors
(including the continued adoption of server virtualization), drives organizations to
acquire additional storage systems or to expand the systems they have. The ongoing
capital expenditure costs are not going away in the foreseeable future. Therefore,
organizations seeking to control costs must look at the OPEX costs associated with
managing their ever-growing storage hardware deployments.
The IBM Storwize V7000 management interface delivers a compelling savings in OPEX
through its highly efficient management capabilities. Edison testing has shown savings
of over 47 percent in administrator time and 31 percent less complexity versus
performing the same set of tasks with EMC Unisphere.
If workload-weighting factors are applied to these results, the savings can be monetized
in average administrator time savings of more than $25,000 per year (34 percent of an
administrator’s time) with the IBM Storwize V7000 management interface over EMC
Unisphere.
Edison believes that, for organizations in need of a mature, stable storage platform for
mid-range enterprise applications, the IBM Storwize V7000 management interface
provides a superior combination of capabilities at a lower OPEX cost than does the EMC
VNX5500.
Edison: Comparing Management Costs for IBM Storwize V7000 and EMC VNX5500 Page 38
Appendices
Appendix I - CMCS Methodology Description
The Methodology Defined
Edison Comparative Manageability Cost Studies methodology is a product
manageability cost-evaluation process. Products in question are compared against a set
of task-oriented objective and subjective metrics in order to derive an accurate set of
analytical results. The outcome of this study determines the Comparative Management
Cost (CMC) incurred by managing and operating the products in a production
environment. The methodology employed to conduct this comparison consists of the
following elements:
The Study
The study is the baseline checklist of standard administration tasks performed routinely,
compared quantitatively and qualitatively to determine, on a task-by-task basis, which
product is superior, primarily in terms of ease of administration. Certain tasks are also
measured in terms of system speed-of-execution — the wall-clock time it takes for the
system to complete a job once it has been submitted by an administrator. The function of
this study is to derive a meaningful set of CMCS statistics that can reveal the real
difference in management costs for the products in question. To do this, CMCS is used
to apply a set of quantitative metrics, developed by Edison Group, to a list of tasks
typically regarded as qualitative in nature.
Tasks
Edison defines a task as a complete logical activity, composed of one or more steps,
which together significantly alter the state of the device or software program that
accomplishes a specific work goal. Each task is measured for time and complexity. Time
and complexity, as used in the study, are defined as follows:
Time
The amount of time it takes to perform a given task. For asynchronous tasks, where a job
can be run in the background while the administrator is accomplishing other things,
time is measured strictly in terms of how long it takes the administrator to perform the
steps to configure, initiate, and submit a given task.
Edison: Comparing Management Costs for IBM Storwize V7000 and EMC VNX5500 Page 39
Other (synchronous) tasks in the study demand the administrator’s full attention and
prevent the accomplishment of other tasks (as in performing a hot recovery operation on
a live database). In that case, time includes both the time it takes for an administrator to
configure/execute the task in question and the time it takes the system to complete the
task. All time metrics are measured in wall-clock time.
Complexity
Complexity is measured using a proprietary metric devised by Edison Group: the
number of system-affecting steps it takes to complete a given task. A step is defined as a
task component that effects a change of state to the system under test.
Because not all steps have the same inherent complexity, each step is further broken
down into increments to account for the difference. An increment is a decision point that
the user must make to complete a step. Increments are technically defined as a part of a
step that will have a measurable effect on the state or execution path, but which does not
itself affect a change upon the underlying system state until the step is complete. For
example, selecting Basic vs. Advanced Install with the installation wizard is an
increment, not a step.
Complexity is then measured in terms of number of steps, but taking into account
the following factors:
The number of increments it takes to complete each step.
Whether or not instrumentation for a given step is GUI-based or requires the use
of a command line/scripting interface.
Whether or not the task requires a context switch between multiple interfaces in
order to be completed. If a context switch exists, then additional steps will be
added to the total step-count for a given task.
The above factors affect the complexity calculation as follows:
The primary measure is steps. If a step has many increments, it is considered several
steps. The metric allows each step five increments, and we add steps for each additional
five increments, rounded up. So if a step has between zero and five increments, it
remains unchanged; if it has between six and 10 increments, it is increased by one;
between 11 and 15 increments, it is increased by two, and so on. We decided to do this
because, while increments are secondary to steps in determining complexity, they do
modify the relative complexity of a given step in the course of completing a task. In
other words, steps with a low number of increments are simple, and steps with a high
number of increments are complex.
Edison: Comparing Management Costs for IBM Storwize V7000 and EMC VNX5500 Page 40
The other modifiers (instrumentation and context switching) may occur very
infrequently in the products under review. Still they are significant enough factors that
we needed to account for them in some meaningful way to generate a measure of
complexity that accurately reflects our experience of using the products.
Regarding instrumentation, if an operation could be executed entirely within a GUI
interface, then the complexity/step value for that task would remain unmodified. If, on
the other hand, a step required the use of a command line interface, this would increase
the step count. For a simple single-line command operation, the step count was
increased by one. Where the operation required the user to write a script, the step value
was increased by two or more, depending on how much work was required to write the
script in question.
Lastly, we come to the matter of context switching. If a context switch was encountered
during the course of completing a given task, then two or more steps were added to the
step count for that task. The possible addition of more than two steps was allowed for as
a judgment call on the part of the subject-matter expert performing the task under
consideration. We regard tasks containing context switches, which require
understanding the dependencies of relating and performing a single operation in two
different environments, as inherently more complex than performing a similar task
when operations can be accomplished in one place.
The following is the complexity formula utilized throughout these studies.
Complexity Calculation Formula
Complexity is defined as the number of computed steps it takes to complete a given
task. The formula Edison typically uses to compute complexity for each of the tasks in
this study is as follows:
For every five increments contained in a step, we increase the step value by one. For
example:
If a step has 0–5 increments, step value = step + 0,
If a step has 6–10 increments, step value = step + 1
If a steps has 11–15 increments, step value = step + 2
… and so on.
The type of instrumentation offered to perform a given task modifies the task’s
complexity.
If a task can be performed completely with a GUI, then step count = step count + 0.
Edison: Comparing Management Costs for IBM Storwize V7000 and EMC VNX5500 Page 41
If a task requires the use of a command line interface, then step count is modified as
follows:
If the command line operation consists of a single-line command, then step count = step
count + 1.
If the command line operation requires writing a script, then step count = step count + 2
or more steps, depending on a subjective assessment of the complexity of the script.
If a task requires a context switch between different environments, then step count =
step count + 2 or more steps, depending on a subjective assessment of the complexity of
the context switch.
Edison: Comparing Management Costs for IBM Storwize V7000 and EMC VNX5500 Page 42
Appendix II - Terminology Glossary
This table lists the equivalent feature nomenclature for the operations and tasks
evaluated in this white paper. The list covers the two vendors with a brief description of
the core functionality and descriptions for each vendor’s implementation of that
functionality. The cell will be blank if the vendor lacks an equivalent feature.
IBM Storwize V7000 EMC VNX5500 Description
Physical Storage
Physical storage is used to
configure and manage
storage pools, internal
and external storage, and
MDisks, and to migrate
existing storage to the
system.
Internal Storage
Internal storage is the
RAID-protected storage
that is directly attached to
the Storwize V7000
system.
Storage Pool
A storage pool is a
collection of MDisks that
jointly contain all of the
data for a specified set of
volumes.
Storage Pool
A storage pool is a means
of storage allocation from
any type of disk and can
incorporate multiple tiers
(Flash, FC, and SATA) in
the same pool. Storage
pools are defined by an
administrator before the
creation of any LUNs.
LUNs can be created at
pool level; these pool
LUNs are no longer bound
to a single storage tier and
can be spread to different
storage tiers within the
same pool.
Some or all of disks in a
system, collected into a
unit of or for virtual
space. (The characteristics
of such collections vary
with vendor).
MDisks
A managed disk (MDisk)
is a logical unit of
physical storage. MDisks
are either arrays (RAID)
from internal storage, or
volumes from external
storage systems. MDisks
are not visible to host
systems.
RAID Groups
A RAID group is a type of
storage pool. It is a set of
disks with a RAID type on
which you create one or
more LUNs with the same
RAID type. The LUN is
distributed equally across
all the disks in the RAID
group.
RAID group is the actual
container for data
protection, where
multiple LUNS or
volumes are created and
assigned to a host.
Edison: Comparing Management Costs for IBM Storwize V7000 and EMC VNX5500 Page 43
IBM Storwize V7000 EMC VNX5500 Description
Volume
A volume is a logical disk
that the system presents
to the hosts. MDisks in a
pool are split into
"extents" of the same size.
Volumes are created from
the extents that are
available in the pool.
There are three types of
volumes: striped,
sequential, and image.
Application servers on
the SAN access volumes,
not MDisks or drives. To
keep a volume accessible
even when an MDisk on
which it depends has
become unavailable, a
mirrored copy can be
added to a selected
volume. Each volume can
have a maximum of two
copies. Each volume copy
is created from a set of
extents in a storage pool.
LUN
A logical unit number
(LUN) is a unique
identifier used to designate
individual or collections of
disk devices for address by
a protocol associated with
a SCSI, iSCSI, Fibre
Channel (FC), or similar
interface.
LUN or volume is a
logical disk created from a
storage pool and assigned
to host. A LUN could
reference an entire RAID
set, a single hard disk, or
multiple disks.
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IBM Storwize V7000 EMC VNX5500 Description
Thin Provisioned
Volumes
When you create a
volume, you can
designate it as thin-
provisioned. A thin-
provisioned volume has a
virtual capacity plus a
real capacity.
Virtual capacity is the
volume storage capacity
that is available to a host.
Real capacity is the
storage capacity that is
allocated to a volume
copy from a storage pool.
In a fully allocated
volume, the virtual
capacity and real capacity
are the same. In a thin-
provisioned volume,
however, the virtual
capacity can be much
larger than the real
capacity.
Thin LUN
A pool LUN with a thin
property. A thin LUN is
able to have a subscribed
user capacity that is
greater than the user
capacity of the shared
pool.
Virtual provisioning/thin
provisioning is a strategy
for efficiently managing
space in a storage area
network (SAN) by
allocating physical
storage on an "as needed"
basis.
This strategy gives a host,
application, or file system
the illusion that it has
more storage than is
physically provided.
Physical storage is
allocated only when the
data is written, rather
than when the application
is initially configured.
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IBM Storwize V7000 EMC VNX5500 Description
FlashCopy
FlashCopy software lets
you make an instant,
point-in-time copy from a
source volume to a target
volume. Without it, if the
data set changes during
the copy operation, the
resulting copy might
contain data that is not
consistent. More
advanced FlashCopy
functions allow
operations to occur on
multiple source and
target volumes.
FlashCopy management
operations are
coordinated to provide a
common, single point-in-
time for copying target
volumes from their
respective source
volumes. This creates a
consistent copy of data
that spans multiple
volumes. The FlashCopy
function also allows
multiple target volumes
to be copied from each
source volume. This can
be used to create images
from different points in
time for each source.
Rollback/Restore
Snapshot or Clones
If the rollback is performed
while a snapshot is still
active to this session, the
snapshot writes will be
copied to the source LUN.
If the snapshot is
deactivated, the original
session data will be copied
to the source LUN.
Snap View
SnapView software lets
you create local point-in-
time snapshots and
complete data copies
(clones) for testing,
backup, and recovery
operations.
Snapshots/Copies are part
of data protection, used in
creating an instant, point-
in-time copy of the source
volumes or LUNS.
It is difficult to make a
consistent copy of a data
set that is constantly
updated; point-in-time
copy techniques help
solve this problem.
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IBM Storwize V7000 EMC VNX5500 Description
Snapshot
The snapshot preset
creates a point-in-time
view of the production
data. A snapshot is not
intended to be an
independent copy, but is
used to maintain a view of
the production data at the
time that the snapshot is
created. Therefore, the
snapshot holds only the
data from regions of the
production volume that
have changed since the
snapshot was created.
Clone
The clone preset creates an
exact replica of the
volume, which can be
changed without
impacting the original
volume. After the copy
operation completes, the
mapping that was created
by the preset is
automatically deleted.
Backup
The backup preset creates
a point-in-time replica of
the production data. After
the copy operation
completes, the backup
view can be refreshed
from production data with
minimal copying of data
from the production
volume to backup volume.
SnapView Snapshot
The defined virtual device
that is presented to a host
and enables visibility into
running sessions. The
snapshot will be defined
under a source LUN in
such a way that activation
of that snapshot will only
be allowed on any running
sessions belonging to that
same source LUN. A
snapshot can only be
assigned to a single
session; thus, to have two
active snapshots for the
same source LUN, you
must have two separate
sessions running in which
to activate two separate
snapshots. Active
snapshots are fully read
and write-capable. Once
the snapshot is
deactivated, however, all
writes to the snapshot will
be deleted.
SnapView Clone
Snap View clones are fully
populated point-in-time
copies of LUNs that allow
incremental
synchronization between
source and destination
LUNs.
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IBM Storwize V7000 EMC VNX5500 Description
Reserved LUN Pool
Collection of LUNs used to
support the pointer-based
design of SnapView. As
the first SnapView session
is started on a given source
LUN, a reserved LUN is
assigned to the source
LUN. If a SnapView
session runs long enough
for the assigned reserved
LUN to be filled, the next
available LUN in the
reserved LUN pool will be
assigned to the source
LUN. Reserved LUNs are
thus assigned on a per-
source-LUN basis, such
that source LUNs have a
one-to-many relationship
to their reserved LUNs.
Server writes made to an
activated snapshot are also
stored on a reserved LUN
in the global reserved LUN
pool. When you deactivate
the snapshot, the reserved
LUN space is freed and all
snapshot writes are
destroyed.
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IBM Storwize V7000 EMC VNX5500 Description
FlashCopy Mappings
A FlashCopy mapping
defines the relationship
between a source volume
and a target volume.
The FlashCopy feature
makes an instant copy of a
volume at the time that it
is started. To create an
instant copy of a volume,
one must first create a
mapping between the
source volume (the disk
that is copied) and the
target volume (the disk
that receives the copy).
The source and target
volumes must be of equal
size.
SnapView Session
This is the process of
defining the point-in-time
designation by invoking
copy-on-first-write activity
for updates to the source
LUN. Starting a session
assigns a reserved LUN to
the source LUN if no other
sessions are running on
this same source LUN.
Note that as far as this
session is concerned, until
a snapshot is activated, the
point-in-time copy is not
visible to any servers.
However, we are tracking
the source LUN so we can,
at any time in the future,
activate a snapshot to this
session in order to present
the point-in-time image
(when the SnapView
session was started) to a
host. As noted earlier, each
source LUN can have up to
eight sessions.
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IBM Storwize V7000 EMC VNX5500 Description
FlashCopy Consistency
Groups
A consistency group is a
container for mappings.
Many mappings can be
added to a consistency
group. Enabling a single,
consistent point-in-time
copy across multiple
volumes, consistency
groups are important in
scenarios, such as a
database environment,
where obtaining a
consistent copy would
require a temporary
suspension of database
operations.
The consistency group is
specified when the
mapping is created. The
consistency group can
also be changed later.
When using a consistency
group, prepare and start
that group instead of the
individual mappings.
This process ensures that
a consistent copy is made
of all the source volumes.
Mappings to control at an
individual level are
known as stand-alone
mappings.
Storage Group
A storage group is a logical
grouping of hosts and
LUNS. The Storage Group
option lets you place LUNs
and hosts into a group so
that the designated LUNs
are accessible only to the
particular hosts included
in the storage group.
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IBM Storwize V7000 EMC VNX5500 Description
Remote Replication
The Metro Mirror and
Global Mirror Copy
Services features enable
IT administrators to set
up a relationship between
two volumes, so that
updates that are made by
an application to one
volume are mirrored on
the other volume. The
volumes can be in the
same system (usually
only for testing purposes)
or on two different
systems (usually at
different physical
locations).
RecoverPoint is a single
solution that provides
host-based and array-
based solutions while
replicating data from any
SAN-based array to any
other SAN-based array
over existing Fibre
Channel or IP network. It
provides the ability to go
back in time and recover
data in a consistent state. It
provides support for
heterogeneous storage,
hosts, networks, and
SANs.