Whitepaper Symantec SFS Introduction to Scalable NAS

7/22/2019 Whitepaper Symantec SFS Introduction to Scalable NAS

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Symantec Technical Network White Paper

WHITE

PAPER:TECHNI

CAL

Confidence in a connected world.

Veritas Storage Foundation

Scalable File Server

Introduction to Scalable NAS for

the Enterprise


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Content

Introduction ..................................................................................................................................... 4Veritas Storage Foundation Scalable File Server Overview ........................................................... 4Gateway Model .................................................................................................................................. 4Leveraging core strengths ................................................................................................................. 6New SFS platform components ....................................................................................................... 7Installation ........................................................................................................................................ 7

Administration .................................................................................................................................. 7NFS File Sharing and Lock Management (NLM) ................................................................................ 8CIFS-based file sharing ..................................................................................................................... 9SFS Key Benefits ............................................................................................................................ 10Consolidate and Reduce Costs of Storage ....................................................................................... 10 Increased Storage Utilization .......................................................................................................... 10Operational Cost Reduction ............................................................................................................ 10Storage Tiering ................................................................................................................................ 11Consolidated Backup/Restore ......................................................................................................... 12Scaling and Seamless Growth ......................................................................................................... 13Modular Growth at the Processing Tier ........................................................................................... 13 Modular Growth at the Storage Tier ................................................................................................ 13Near Linear Scaling ......................................................................................................................... 14Availability, zero interruption of file services for company critical data ......................................... 15 Example Use Case .......................................................................................................................... 16Enable scale out compute clusters and heterogeneous sharing of data ......................................... 16Infrastructure checklist ................................................................................................................. 17SFS Server Hardware Requirements ............................................................................................... 17SFS Storage Hardware Requirements ............................................................................................. 17Summary ........................................................................................................................................ 18Where to get more information ....................................................................................................... 18

White Paper: Symantec Technical

Veritas Storage Foundation Scalable File

System

Introduction to Scalable NAS for the

Enterprise


3/19

Symantec Technical Network White Paper


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About Technical White Paper

4

Introduction

This document provides a technical introduction to and outlines the various use cases for the

Veritas Storage Foundation Scalable File Server (SFS) product. SFS is a high-performance, highly

scalable clustered NAS solution, delivered in a software appliance-style packaging. Taking

advantage of the rock-solid stability of the Storage Foundation Cluster File System (CFS), SFS

delivers NFS and CIFS-based file serving, along with integrated storage tiering and other high-end

NAS functionality.

As a clustered NAS product, SFS has a singular function: to share out unstructured file data in a

simple-to-operate, highly scalable, and highly available manner. Unlike in a typical CFS

deployment, one cannot run other applications on SFS nodes. While a customer could configure

core CFS to only serve out NFS file systems and then add a CIFS-based file-sharing package (e.g.

Samba), this is an unlikely use case due to operational heaviness associated with maintaining all

the core CFS components, CVM, CFS, VCS, GAB/LLT, DMP, and then adding the complexities of

different NFS server implementations and samba install. SFS masks all of these components and

provides a simple, appliance-like administration model for file serving. This document describes

a technical overview of the Scalable File Server and the benefits to deploying the product in a file

serving environment.

Veritas Storage Foundation Scalable File Server Overview

Storage Foundation Scalable File Server is a fixed function, soft appliance based extensively on

Storage Foundation technology, including using CFS as a core file system engine and Veritas

Cluster Server (VCS) cluster technology to allow seamless scaling of the SFS cluster. The

applications consuming the storage are running a standard NFS or CIFS-based client.

Components of SFS include the underlying, hardened Linux operating system, CFS, and the new

SFS platform components all provided on a single DVD image.

Gateway Model

SFS is built on a NAS gateway architecture model. The SFS software can be installed on an

industry standard sever running Intel Xeon-based processor architectures. These servers can be

blade or other form factors.


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The SFS servers are then attached via Fibre Channel to FC-attached storage. This can be separate

FC storage connected through a commodity switch (or point-to-point in a two-node cluster), or

connected to and part of a much larger SAN. In all cases, the connections are made via one or

more FC HBAs in each of the SFS nodes. Thus the solution is an open storage offering allowing a

high degree of flexibility in configuration. Customers can attach different storage devices to the

SFS cluster ranging from commodity storage to high-end arrays. Support for nearly all storage

arrays that present valid SCSI-3 LUNs is provided, and there is additional support for

active/active arrays through the Storage Foundation Dynamic Multi-Pathing. Full details on thissupport can be found in the Storage Foundation Hardware Compatibility List, obtainable through

the Symantec support website.

Figure 1 shows the conceptual model of a clustered gateway model. The diagram shows the front

end IP network to handle NFS client requests and the backend heterogeneous Fibre Channel

based storage tier.

Figure 1 Clustered Gateway Model


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Leveraging core strengths

In addition to the Scalable File Server platform itself, SFS also leverages the capabilities and

strengths of the core CFS file system engine and Veritas Cluster Server HA capabilities. Some of

these key features include Dynamic Multi-pathing (DMP), the cluster file system (CFS), Veritas

Cluster Server (VCS) and Dynamic Storage tiering (DST). Each of these layers represents

industry-leading technology solutions and when combined into a file serving appliance provide an

incredibly robust foundation on which to host file services.

CFS is the underlying core file system technology that is used within SFS. CFS itself is built upon

the industry-leading Veritas File System (VxFS). CFS provides full POSIX compliance; cache

consistency across multiple nodes, a single namespace and a global lock management

implementation. CFS also distributes load across SFS cluster nodes so that both data and meta-

data operations can be performed for the same file system across the cluster. This leads to near-

linear scalability in terms of NFS operations per second. For SFS, leveraging the maturity and

scalability of CFS was critical in being able to ensure the mission-critical and rock-solid

performance and availability that is expected in todays high performance storage environments.

DMP provides advanced FC HBA load balancing policies and tight integration with array vendors

to provide in-depth failure detection and path failover logic. DMP itself is a large technical

differentiator when evaluating SFS against similar offerings from other vendors as it contains the

most advanced capabilities of any multi-pathing driver in the industry.

Finally, VCS itself is used within SFS to provide cluster wide monitoring, communication, and

failover for all nodes and their associated critical resources including virtual IP addressing

failover for both NFS and CIFS client connections.


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New SFS platform components

The following section outlines the new modules that SFS is comprised of in order to provide a

complete file-serving solution.

Installation

The first node in an SFS cluster is booted from a single DVD containing the OS image, and SFS

software stack which is comprised of: The Storage Foundation Cluster Volume Manager, Storage

Foundation Cluster File System, and the Storage Foundation Scalable File Server platform. Once

this node is up and running the rest of the nodes in the cluster (defined via IP addresses during

the first node boot up) are automatically installed over the SFS private network with all necessary

components (these nodes can also be imaged and installed at a later date). Key SFS services are

then automatically started to allow the cluster to begin discovering storage and creating NFS or

CIFS shares.

Administration

SFS contains a role-based administration model consisting of three key roles: Storage, Master,

and Network. This delineation is consistent with the operational roles in many data centers. For

each role the administrator accesses an easy-to-use Command Line Interface (CLI). This CLI

provides for a common and consistent access method to all aspects of SFS administration,

including managing storage, creating shares, administering network interfaces, etc. Furthermore,

an administrator can simply log in as one of those roles on the console node within the cluster

(normally the first node that was installed) and can then execute commands which perform tasks

uniformly on all nodes in the cluster.

A specific design goal of the SFS product was that there should be no requirement to have any

knowledge of Veritas Storage Foundation technology to install or administer an SFS cluster. In

fact, there is no need to have any specific understanding of any Veritas technology, as the SFS

CLI masks any of the components and provides a single point of administration for the entire

cluster. Of course, it should also be noted that users currently familiar with Storage Foundation

technology will find familiarity with the basic management concepts.


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Adding or removing nodes from the SFS cluster is a simple non-disruptive operation and is highly

automated following the installation model outlined above.

NFS File Sharing and Lock Management (NLM)

SFS provides for active/active shared data NFS file sharing across all nodes within the SFS

storage cluster. This provides for unparalleled scalability as clients are free to access any node

within the cluster at any time, and be able to access the same data both read and write. This

allows for the ability to load-balance across an SFS cluster by dividing access to specific nodes,and also allows the administrator to perform manual load-balancing correction by moving Virtual

IP addresses between the storage cluster, when needed.

Because NFS can be shared read/write across all nodes, SFS has implemented the NFS NLM

module which allows a customer to use NFS advisory client locking in parallel with core CFS

Global Lock management. The module consists of failing over the locks amongst SFS nodes as

well as forwarding all NFS client lock requests to a single NFS lock master. The result is that no

data corruption will occur if a user or application needs to use NFS client locking with an SFS

cluster.


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Figure 2 below depicts the architecture components of the SFS stack. The components in blue

are elements leveraged from the core CFS stack or the base O/S architecture, while the brown

components indicate the new SFS additions. CIFS file serving functionality was added into the

SFS 5.0.1 release.

Figure 2 SFS Component Architecture

CIFS-based file sharing

With the 5.0.1 release of SFS, CIFS file services functionality was added to the product. CIFS file

sharing is made possible in SFS with the use of the open-source Samba file sharing package.

Within an SFS cluster, all nodes can be running and sharing data over CIFS; further, CIFS shares

can be failed-over to other nodes in the cluster, and the DFS referral functionality can also be

utilized in order to span CIFS shares across all nodes, e.g. in a Homedirs environment. Full

integration with Active Directory is also provided.


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SFS Key Benefits

The following represent the most common uses cases or likely deployment scenarios for the SFS

product. This list is not exclusive or comprehensive but should provide the reader with a good

understanding of how and when to use SFS to solve key business problems.

Consolidate and Reduce Costs of Storage

The value of consolidating several independent islands of NAS storage into fewer, larger shared

pools has many cost benefits which are outlined below.

Increased Storage Utilization

Typical enterprises are running with storage utilization rates in the 30 40% range. This results

in excessive spending on new storage when there is more than adequate free space in the data

center. Ideally customers would group their storage assets into fewer, larger shared pools. This

would naturally result in a significant increase of backend storage utilization. In turn, this

increased efficiency would then result in substantial cost savings from deferred purchases of new

storage. SFS allows the creation of larger pools due to its scalable front processing capabilities.

Eight mid-range nodes can provide over 1.6 GBytes/sec of aggregate throughput which facilitates

very large backend pools. This assumes each SFS node is configured with 2 GbE NICs for NFS

client data traffic. More GbE NICs could be configured if required. With combined NFS and CIFS

file sharing, the storage pool can be securely shared amongst heterogeneous or homogeneous

nodes. Thus, SFS becomes a powerful enabler for this common business strategy.

Operational Cost Reduction

The use of NAS heads from traditional storage companies have resulted in the proliferation of

many independent islands of NAS storage. As the number of islands increases, the operational

burden of managing these many NAS head-to-storage relationships becomes a significant time

investment both from a technical and business perspective. Fewer, consolidated pools that

can be spanned across multiple SFS clusters reduces the ongoing management costs since there

are a fewer relationships to manage.


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Storage Tiering

Being able to seamlessly tier unstructured data between different types of storage media is a

natural fit in the NAS market. Despite this, few customers have adopted a storage tiering strategy

even though the business benefits are clear. This is generally because, there are many

limitations with the legacy or current storage tiering offerings in the market today that are

causing this slow rate of adoption. Most commonly, the lack of flexibility of static storage tiering

solutions is the biggest barrier; tiering that occurs at a hardware block level, rather than at the

file level is counter-intuitive to what would be expected within a NAS solution. Furthermore, suchhardware based data relocation solutions often restrict support for hardware from only the same

vendor, and further limit granularity to a LUN level even if there is a degree of abstraction

provided. There is no visibility to the underlying individual files and directories. The effectiveness

of these types of solution is further diminished when the often high overhead of carrying out

such relocation operations is taken into consideration.

SFS includes a native storage tiering solution that is integrated into the product, and that

leverages existing Veritas technology. The DST feature that was first introduced into the Veritas

File System (VxFS), and later implemented into CFS and also SFS provides the unique ability to

meet all of the key requirements customers need from a tiering solution. With SFS, tiering is pre-configured and defined meaning it simply needs to be enabled on a storage pool basis to work.

An administrator specifies the number of days before primary storage will tier to secondary, and

once enabled, the process is automatic. In addition, such tiering happens on a file level, without

affecting the files location, or its i-node credentials. With SFS, this DST functionality also scales

seamlessly to match the environment being used; relocation is quick and effective for millions of

files due to the use of the Veritas File Change Log (FCL) a feature whereby the SFS server nodes

can track which files have changed and need to be relocated, without having to walk the file

system.

Finally, in SFS, the storage can always be heterogeneous including when using storage tiering.

Being able to tier between different storage vendors, and/or different storage technologies is all

fully supported. A common use when dealing with large repositories of unstructured data is to

utilize a MAID-style architecture for the secondary tier. In a use case where high-performance is

key, utilizing solid-state disk (SSD) on the primary tier is also possible.


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Figure 3 below depicts the unique feature of SFS, the multi-volume file system, and how it

maintains the application transparency. SFS can leverage this capability to further reduce costs

of the backend FC storage by moving older data to lower cost storage.

Figure 3 Multi-volume File System Namespace

Consolidated Backup/Restore

A consolidated set of large storage pools reduces the management overhead of backing up and

restoring disjointed file systems. With a 256TB maximum filesystem size, SFS allows the

collapsing of the file storage into fewer pools and thus reduces the backup interfaces and

operations necessary. All critical file data can be backed up and restored through the SAN via

integration with the market leading Veritas NetBackup (NBU) solution.


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Scaling and Seamless Growth

SFS allows a customer to scale storage and processing independently and seamlessly (online).

This provides great flexibility since a given application may need to scale in either dimension.

The application may be primarily performance based and additional throughput may be needed

for the same amount of storage; or perhaps the application is capacity bound and thus only

needs to add backend storage without adding an SFS node. You can add only the resources that

the application(s) require without having to purchase a costly combined set of compute and

storage resources.

Modular Growth at the Processing Tier

SFS automates the installation of a new node to the running cluster, configures it, and adds its

capacity into the processing tier. The product scales from 1- 8 nodes today, with 16 nodes

planned for the next major release update. An administrator can quickly add processing in units

of single nodes, providing modular scaling that leverages cost savings compared to buying a large

new and costly independent appliance, and without adding to the management burden.

Modular Growth at the Storage Tier

SFS takes advantage of Veritas CVM and DMP technology in order to discover and use new

storage resources; this is also an on-line operation that requires no downtime on any node. A

storage administrator can configure a new array or even add new LUNs from existing ones to the

SFS cluster nodes. SFS can then scan the storage automatically, see the new LUNs, and place

them under SFS control for use in the file systems.


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Additionally, at the storage tier, existing file systems can be dynamically resized (shrink/grow)

on-line with no interruption of service. There is a simple command to add space to an existing

file system which automatically uses newly available storage. Existing files system shares can

be reduced in size in order to free up or reclaim tier-one storage. SFS creates the concept of a

logical storage pool, from which volumes and file systems can be created and managed. Mirroring

and tiering is all supported at a storage pool layer; additionally, the ability to perform SFS level

RAID mirroring is built into SFS, thus allowing an administrator to utilize RAID protection at both

an array level (e.g. RAID 6), and use mirroring across arrays at a SFS storage level. Finally, SFSprovides the flexibility for an administrator to specify which LUNs a given file system should

reside on within a storage pool. This can be critical for some performance based applications.

SFS growth allows a customer to adopt a pay as you grow model. This is often highly desirable

for service providers or any customer who has implemented a chargeback model.

Near Linear Scaling

The product provides nearly linear scaling in terms of both NFS operations per second as well as

total I/O throughput. Figure 4 below depicts this scaling capability.


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Figure 4 SFS ScalabilityNote: SFS is initially qualified to support up to 8 nodes for the 5.0 product release. 16 nodesupport will be added in the next major release update of SFS.

Availability, zero interruption of file services for company critical data

SFS provides an always-on file service. The loss of single or even multiple nodes does not

interrupt I/O operations on the client tier. The convergence of two key trends is driving the

capabilities that SFS delivers: The first is the dramatic growth of file based (unstructured) data

assets. The second is the critical nature of these assets; they have to be available at all times to

the application.

The architecture provides transparent failover for other key services such as NFS lock state,

reporting and logging, and backup and restore operations. The installation service itself is also

highly available and can seamlessly recover from the initially installed node failing during the

install of the remaining nodes in the cluster. In the event of a CIFS failover, users simply re-

establish their session and connect to a new node within the SFS cluster. Finally, the console

service providing access to the centralized menu driven interface is automatically failed over.


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Example Use Case

Enable scale out compute clusters and heterogeneous sharing of data

The trend to scale out, aka Grid computing continues to gain significant traction in both the

server and storage industry.

One of the key inhibitors to this scale out computing is the requirement to provide a shared

storage infrastructure for compute nodes. There are few cost effective options available todaythat enable you to share storage heterogeneously as well as scale up as performance requires.

SFS solves both of these issues by providing a highly scalable and shared storage platform at the

storage tier and by scaling file services such as NFS and CIFS on the compute tier.

An example architecture might look like the following: An existing infrastructure houses

approximately 15TB of audio files in the form of voicemail data. This data is housed on a

traditional NAS platform. A series of twelve Linux blade servers are used to process call data, and

to write new files to the existing file system. A separate system is used to handle long-term

archiving of the call data, with a third system used to run reports on average call length, number

of voicemail files stored, etc. All of these servers need access to the same files and there is an

application requirement to have all of the files within a single namespace. Because the nature of

these files is to be written once, read for a short period of time and then archived, a storage

tiering strategy is desirable; one that can scale to 128TB+ (catering for growth) and still maintain

a single namespace. A single NAS head or two heads in an active/passive configuration cannot

provide enough NFS file serving performance to meet the throughput and response time

requirements, and additionally, the existing NAS solution limits the maximum file system size to

16TB. In this use case, SFS can provide the performance and availability necessary for the NFS

storage tier by spanning a single namespace across multiple nodes. Add in the built-in storage

tiering that will allow the use of additional MAID-style storage architecture in addition to primarySATA drives, and SFS is clearly wells-suited for this use case. SFS provides more than adequate

throughput and seamless failover for this architecture and also places no limits on the number of

spindles used, and allows a single file system to be 256TB in size more than enough for the

growth plans at this customer.


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Infrastructure checklist

SFS Server Hardware Requirements

The server hardware must be capable of running SUSE Linux Enterprise Server 9 SP3 forAMD64 and Intel EM64T.

o Dual or Quad core processors at 3.0 GHz or above, are recommended forperformance

o Itanium is not supported 8 GB Minimum error-correcting code (ECC) random-access memory (RAM).

o

16 GB recommended Internal Drives: Minimum single disk, dual drives recommended 4 Gigabit Ethernet NIC Ports

o Dual embedded Gigabit Etherneto 2 Additional Gigabit Ethernet

2 Fiber Channel HBAs Internal DVD Drive PXE Boot capable BIOS Redundant power supply

SFS Storage Hardware Requirements

In general, SFS supports any FC attach storage that presents SCSI-3 valid LUNs. Please review the

following document from the public support website for specific details on supported arrays and

array vendors:

http://seer.entsupport.symantec.com/docs/283161.htm
http://seer.entsupport.symantec.com/docs/283161.htmhttp://seer.entsupport.symantec.com/docs/283161.htmhttp://seer.entsupport.symantec.com/docs/283161.htm


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Summary

Veritas Storage Foundation Scalable File Server from Symantec is a clustered NAS file serving

appliance that provides enterprise-wide CIFS and NFS file services in a highly available and

scalable environment. The server software is installed on industry standard hardware to give IT

organizations flexibility in choice of hardware vendors. SFS is based on the industry-proven

Veritas Storage Foundation Cluster File System.

Additional SFS servers can be added to the cluster without disruption and the file system can begrown dynamically without affecting file services. SFS combines the stability of a well-proven

product with enterprise-class scalability, low cost of deployment, and a simplified administration

model.

SFS lowers the cost of NAS file serving by reducing the proliferation of storage islands, reducing

the complexity of storage management and by improving storage utilization.

Where to get more information

More information can be found on theScalable File Serverpages at Symantec.com
http://www.symantec.com/business/storage-foundation-scalable-file-serverhttp://www.symantec.com/business/storage-foundation-scalable-file-serverhttp://www.symantec.com/business/storage-foundation-scalable-file-serverhttp://www.symantec.com/business/storage-foundation-scalable-file-server


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About Symantec

Symantec is a global leader in

infrastructure software, enabling

businesses and consumers to

have confidence in a connected

world. The company helpscustomers protect their

infrastructure, information, and

interactions by delivering

software and services that

address risks to security,

availability, compliance, and

performance. Headquartered in

Cupertino, Calif., Symantec has

operations in 40 countries. More

information is available at

www.symantec.com.

For specific country offices and

contact numbers, please visit

our Web site. For product

information in the U.S., call

toll-free 1 (800) 745 6054.

Symantec Corporation

World Headquarters

20330 Stevens Creek Boulevard

Cupertino, CA 95014 USA

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1 (800) 721 3934

www.symantec.com

Copyright 2008 Symantec Corporation. All rights reserved.

Symantec and the Symantec logo are trademarks or

registered trademarks of Symantec Corporation or its

affiliates in the U.S. and other countries. Other names may be

trademarks of their respective owners.

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Whitepaper Symantec SFS Introduction to Scalable NAS