62 2012 Issue 04 | dell.com/powersolutions

Managing the data delugeFeaturesection

Reprinted from Dell Power Solutions, 2012 Issue 4. Copyright © 2012 Dell Inc. All rights reserved. Reprinted from Dell Power Solutions, 2012 Issue 4. Copyright © 2012 Dell Inc. All rights reserved.

Today IT is at the heart of productivity

and revenue generation, whether an

organization is a small or medium

business at a single domestic location,

a large enterprise with locations worldwide, or

somewhere in between. Now more than ever,

organizations of all sizes are looking to boost agility

and flexibility so they can keep up with ever-changing

capacity and performance demands. Effective data

management helps organizations meet mounting

challenges within the confines of tight IT budgets and

condensed staffing.

Decision makers now have advanced data

center technology options they can leverage to

help enhance performance, improve workload

and application processing, and optimize resource

utilization and operational efficiency.

Dell PowerVault MD3 Series storage area

network (SAN) Internet SCSI (iSCSI) arrays, in

particular, are designed to provide a reliable, flexible,

efficient, and cost-effective platform that empowers

organizations to achieve desired business outcomes

(see Figure 1). With the launch of PowerVault MD3

Series feature enhancements, advanced data

management and protection have been added to

a rich feature set that enables tremendous agility,

flexibility, and efficiency for IT organizations in

managing their data center environments.

Minimizing drive failure recovery time

A primary concern for storage administrators is

managing a complex environment and losing data. To

protect an organization’s data, storage administrators

use advanced features and various levels of protection

such as RAID groups and snapshots. While traditional

RAID protects data from a single or multiple drive

failure, it can be difficult to configure, and in the event

of a drive loss, recovery time—and subsequently the

data loss window—is proportional to the RAID type and

size as well as the type of hard drive.

As drive capacities expand, the time necessary for

traditional RAID systems to rebuild to an idle spare

after a drive failure is increasing because the idle

spare gets all the write traffic during a rebuild. That

traffic can slow down the system and data access

during the rebuild operation.

Dynamic Disk Pool (DDP) provides an advanced,

easy-to-use feature for managing disk groups and

Robust storage for agile data management

The dynamic nature of data can quickly swell capacity

and performance demands in any organization.

Feature-rich Dell™ PowerVault™ MD3 Series arrays offer

easy-to-manage storage designed to scale capacity,

boost performance, and save capital costs.

By Vamsee Kasavajhala

Powerful data management

Designed for high availability and easy scalability, Dell PowerVault

MD3 Series arrays deliver efficient data management, protection,

and recovery capabilities for organizations of all sizes.

dell.com/powersolutions | 2012 Issue 04 63

Managing the data delugeFeaturesection

Reprinted from Dell Power Solutions, 2012 Issue 4. Copyright © 2012 Dell Inc. All rights reserved. Reprinted from Dell Power Solutions, 2012 Issue 4. Copyright © 2012 Dell Inc. All rights reserved.

administering a storage environment, and

it offers faster recovery time from a disk

failure than a traditional RAID system. The

DDP feature is designed to allow all the

drives to work in parallel, enabling much

faster recovery times than traditional

RAID systems allow (see Figure 2).1 Fast

recovery times help reduce the risk

window for data loss. As a result, DDP

benefits can be an important consideration

when administrators evaluate which data

protection features may best suit their

deployment (see Figure 3).

In addition, the DDP algorithm prioritizes

the rebuilding of critical segments of data,

once those segments are recovered; then

the system is designed to sustain even a

third drive failure. To extend the concept,

once the third drive’s critical segments are

recovered, a fourth drive failure can be

sustained, and so on. Traditional RAID, in

contrast, does not provide this flexibility.

DDP helps avoid storage emergencies by

making an individual drive loss a nonevent.

When utilizing DDP, storage administrators

do not have to manage idle spares. DDP

allows for any number of drives in a pool,

which helps simplify adding or removing

drives from a pool. When a drive is added or

removed, DDP is designed to rebalance the

data across the available drives.

Gaining dynamic capacity

with thin provisioning

Storage administrators face many decisions

daily, and one particularly challenging

decision is estimating the amount of

storage an application requires. For

example, a pharmaceutical company

starting a research project may expect

its databases to grow 10 times during a

two-year period—requiring 11 TB capacity.

If the administrator in this example

immediately provisions that estimated

storage requirement, a significant amount

of storage resources will be allocated but

remain unused for much of that time—

causing an inefficient use of capital.

The other option—increasing storage

capacity on the server repeatedly over

Figure 1. PowerVault MD3 Series storage platform designed for performance, reliability, scalability, and ease of management

Figure 2. Drive failure recovery times for nearline SAS drives in a dynamic disk pool and a traditional RAID-6 group

Ease of management

Performance

Tremendously high reliability

Flexible optionsFibre Channel and iSCSI connectivity

and SAS and nearline SAS drives, SSDs, and SEDs

Scalable to 192 drives

Dell PowerVaultMD3 Series storageDensity

4U enclosure with 60 drivesor 2U enclosure with 12 or 24 drives

5040

30

20

10

0

6070

80

90

100

Application

OS

Application

OS

120

100

80

60

40

20

0

Ho

urs

re

qu

ire

dfo

r d

rive

fai

lure

re

cove

ry

One drive failure Two drive failures

Traditional RAID-6

Dynamic disk pool

3 TB nearline SAS drives

51 hours

100 hours

8 hours 12 hours

1 Based on August 2012 testing at Dell Labs by Dell engineers comparing drive failure recovery between 3 TB nearline SAS drives in a DDP and traditional RAID-6.

64 2012 Issue 04 | dell.com/powersolutions

Managing the data delugeFeaturesection

Reprinted from Dell Power Solutions, 2012 Issue 4. Copyright © 2012 Dell Inc. All rights reserved. Reprinted from Dell Power Solutions, 2012 Issue 4. Copyright © 2012 Dell Inc. All rights reserved.

time—commonly requires working after

hours, bringing systems down, and disrupting

operations each time. The administrator in

this case has the option of overprovisioning to

simplify management or growing multiple times

and suffering the consequences, which may

lead to a trade-off between capital costs and

management costs.

Thin provisioning can provide the

advantages of both strategies in this scenario.

It enables the administrator to logically

overprovision storage to the application

but physically provision only the storage

that is needed, and growth can occur

automatically over time. This approach allows

the administrator to achieve management

goals without disruption, while contributing to

capital cost reduction goals that help ensure

benefit gains from future storage technology

advancements. Note: Thin provisioning is

supported only on DDP disks.

Optimizing applications

in virtualized environments

Organizations of all sizes are moving applications

to virtualized environments as a means of

helping reduce capital and operational costs.

Data management and protection capabilities in

Dell PowerVault MD3 Series storage as well as an

optional high-performance tier for maximizing

read/write access enhance performance and

availability to optimize application delivery as

virtualization is extended throughout the data

center (see Figure 4).

Solid-state drive cache

To meet today’s enterprise requirements, Web,

cloud, and virtualized applications require both

high capacity and performance. Hard disk drives

(HDDs) including Serial Attached SCSI (SAS)

and nearline SAS drives and self-encrypting

drives (SEDs) provide capacity but not top

performance. Solid-state drives (SSDs), on the

other hand, provide outstanding performance but

may compel administrators to compromise on

capacity and cost.

PowerVault MD3 Series storage arrays offer

an SSD cache feature that lets administrators

combine the advantages of HDDs and SSDs in

one cost-effective storage solution. SSD cache

enables PowerVault MD3 Series arrays to

add SSDs and use them as extended cache to

optimize performance of the entire storage

system. The controller dynamically adapts to

the data being used and automatically moves

frequently used data to fast SSDs to accelerate

overall read performance. Applications

characterized predominantly by read operations

can benefit from the SSD cache feature.

Disk storage function offloading

With large hypervisor-based implementations,

optimizing application computation rather than

the actual data management tasks on the servers

Traditional RAID DDP DDP benefit

Array and logical drives

Drives are typically optimized for enclosure utilization; spare drives are idle.

Data, protection information, and spare capacity are spread across all drives in the disk pool.

DDP offers easy administration and enhanced utilization of purchased capacity.

Drive rebuild A single drive, a hot spare, is used for all rebuild writes—a slow process—and it impacts all logical drives in the array.

All drives share in the rebuild— a fast process—minimizing impact to all logical drives in the disk pool.

DDP enables a significant reduction in the impact of a drive failure.

Array expansion

Logical drives are restriped across a new group.

Data is dynamically redistributed to new drives.

The array is back to optimal operation in minimal time.

Note: DDP and RAID can coexist in an array. An administrator does not have to select either feature, and DDP is designed to perform well in a mixed-workload environment.

Figure 3. Benefits of a dynamic disk pool (DDP) in contrast to traditional RAID

dell.com/powersolutions | 2012 Issue 04 65

Managing the data delugeFeaturesection

Reprinted from Dell Power Solutions, 2012 Issue 4. Copyright © 2012 Dell Inc. All rights reserved. Reprinted from Dell Power Solutions, 2012 Issue 4. Copyright © 2012 Dell Inc. All rights reserved.

has become critical to maximize compute

resources. VMware vSphere® Storage

APIs – Array Integration (VAAI) is an

application programming interface (API) with

a set of primitives that enable the offload of

specific disk storage–related functions from

a VMware® ESX® hypervisor to the storage

array controllers. Offloading these functions

can free network bandwidth and host

compute resources by allowing PowerVault

MD3 Series arrays to perform tasks such

as full copy, block zeroing, and hardware-

assisted locking. Delegating these tasks to

the SAN layer enables quick deployment

of virtual machines from templates and

enhanced storage performance for volumes

shared by multiple virtual machines. In

addition to VAAI, PowerVault MD3 Series

arrays feature the Dell PowerVault MD3

Series Plug-In for VMware vCenter. The

plug-in enables VMware administrators

to monitor and manage the arrays in

conjunction with VMware virtualization, and

VMware vSphere Storage APIs for Storage

Awareness (VASA) provides coordination

between VMware vCenter™ software and

PowerVault MD3 Series arrays.

Disaster recovery

Because organizations continue to work

with ever-increasing amounts of data,

protecting vital data is no longer simply a

matter of copying changed files to tape.

Data protection has grown increasingly

complex because critical data changes

occur throughout the workday, and this

data requires protection against damage,

loss, and lack of availability. PowerVault

MD3 Series arrays are designed to provide

advanced protection capabilities. Snapshots

offer point-in-time copies of data for

easy recovery of files altered accidentally

or deleted. Virtual disk copy provides

comprehensive replication of source

data that enables quick, seamless virtual

disk relocation and disk-based backup

and recovery. And remote replication—

previously only available on PowerVault

MD3 Series Fibre Channel arrays—allows

data to be replicated remotely from one

PowerVault MD3 Series array to another.

Using the Dell PowerVault MD Storage

Array VMware Storage Replication Adapter

(SRA), remote replication is tightly integrated

with VMware vCenter Site Recovery

Manager (SRM) software to facilitate

centralized disaster recovery management,

automation, and testing for virtualized

data centers. SRM enables nondisruptive,

automated testing of recovery plans

and automates the recovery process,

while the PowerVault MD3 Series arrays

supply cost-effective and easy-to-configure

replication over existing IP networks.

The core server virtualization

platform that provides IT environments

with the tools to help reduce the cost

and complexity of managing their IT

infrastructure can now be expanded

to help simplify disaster recovery as

well. Storage and server virtualization

solutions from Dell and VMware provide

a comprehensive, virtualized data center

that enables a dynamic, highly automated

computing environment.

Maximizing performance

with feature-rich storage

Business growth for organizations

spanning small and medium businesses to

large enterprises requires storage that can

scale in capacity, flexibility, performance,

and manageability. Dell PowerVault MD3

Series feature enhancements include many

high-end storage capabilities, offering

organizations of all sizes efficient, cost-

effective, and easy-to-manage storage

arrays that support effective application

delivery in virtualized environments.

Learn more

Dell PowerVault storage:

dell.com/powervault

Dell PowerVault MD Series resources:

dell.com/pvresources

Author

Vamsee Kasavajhala is a technical

marketing senior advisor for Dell PowerVault

storage solutions.

Figure 4. Key software features in PowerVault MD3 Series arrays

High-performance tier:Optimized, high-speed

read/write access

Thin provisioning:Storage is provisioned as needed

VMware virtualization:Integrated VAAI, VASA,

Dell PowerVault MD StorageArray VMware SRA, and

Dell PowerVault MD3 SeriesPlug-In for VMware vCenter

SSD cache:Hot data stored on SSDs

Dell PowerVaultMD3 Series storage

Application

OS

Application

OS

DDP:Tremendous data availability,

dynamic recovery, no downtime,and ease of use

Data protection:Snapshots, virtual disk copy,

and remote replication