Whitepaper - Server Virtual is at Ion and Storage Management

8/14/2019 Whitepaper - Server Virtual is at Ion and Storage Management

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Server

Virtualisation

AndStorage

Management

Optimising Storage Management to Obtain

Greater Benefits from Server Virtualisation

Alan McSweeney


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ServerVirtualisation and Storage Management

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Contents

Server Virtualisation........................................................................................3Server Virtualisation Architecture....................................................................4

Configuration ...............................................................................................4Virtual Server Resilience ..............................................................................4

Virtual Server Data Backup and Recovery ...................................................5

Storage Management and Server Virtualisation................................................6Virtual Server Backup and Recovery............................................................8IBM N Series SnapMirror .............................................................................9IBM N Series FlexVol and FlexClone............................................................9IBM N Series RAID Double Parity ..............................................................9Conclusion..................................................................................................10


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Server Virtualisation and Storage Management

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Server Virtualisation

Implementing server virtualisation (using software such as VMware) can deliver

substantial benefits to IT and business by reducing the number of deployed

Intel-based servers by 50% or more while delivering benefits such as:

Improved server utilisation rates - 60% to 80% (up from typical rates of lessthan 15%)

Server and application provisioning time measured in hours not days Reduction in downtime such as hardware maintenance Reduction in operating costs Increased server and application resilience Simplification of server operation and administration Increased levels of serviceImplementing server virtualisation also provides a platform for:

Facilitating business continuity and disaster recovery Improved backup and recoveryA little additional planning and investment will deliver significant additional

benefits for a virtualised server environment in terms of:

Faster backup and recovery Protection against application corruption

Improved business continuity and disaster recovery

Implementing server virtualisation requires some form of shared storage to

enable features such as HA (High Availability) and DRS (Dynamic Resource

Scheduling).

In order to implement an effective, efficient, resilient and performing virtualised

server infrastructure, the storage component needs to be designed correctly.

This can include taking advantage of features in a virtualised server

infrastructure such as snapshotting and virtual backup.

This whitepaper discusses some of the issues regarding the configuration of

storage for server virtualisation to derive a more complete set of benefits.

This whitepaper makes reference to one storage subsystem from NetApp and

also sold by IBM as the N Series.

Once confined to server

rooms, virtualization has

now made it into the

mainstream of computing.

And by 2010,

virtualization will be the

single most important

technology for IT

departments, according toresearch firm Gartner.


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Server Virtualisation Architecture

Configuration

Optimising the benefits of server virtualisation will involve implementing a

virtualisation infrastructure along the following lines:

There will be two (or more) sets of physical servers onto which servers are

virtualised. These can be configured to operate as active/active or active/passive.

The physical servers will be connected to shared storage such as a fibre-channel

or iSCSI SAN.

The I/O load that was distributed across a large number of separate physical

servers is now concentrated onto a smaller number of servers hosting the virtual

servers.

Virtual Server Resilience

A configuration such as this provides multiple points of resilience

80% of businesseshave no plan

o It wonthappen to

me

68% of businesseswho experience a

disaster and dont

have a plan go out

of business within 2

years

One in fiveorganisations will

suffer a major IT

disaster in five

years

A companyexperiencing a

computer outagelasting longer than

10 days will never

fully recover


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In the event of the failure of a physical server within the virtual infrastructure

the virtual servers can be restarted on either another server within the same

infrastructure or to a server on the other infrastructure.

Virtual Server Data Backup and Recovery

There are two options for backing-up virtual servers within a virtual

infrastructure using software-based backups:

1. The existing process for backing-up physical servers can be implemented inthe virtual environment backup agents for your existing backup tool can

be installed on the virtual servers and these servers backed-up as normal.

2. Using VCB (Virtual Consolidated Backup) to capture server images theentire virtual server can be backed-up to a separate Proxy Server that can

then backup the images using existing backup software. A backup agent for

your existing backup software is installed on the VCB server. This reduces

backup software costs but decreases the granularity of what can berecovered.

Standard Server Backup Virtual Consolidated Backup


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Storage Management and Server Virtualisation

In a virtualised server environment, storage and its management assumes a

greater importance that for normal server configurations:

Shared storage in the form of a SAN is required to take advantage ofadvanced virtualisation features such as HA (High Availability) and DRS

(Dynamic Resource Scheduling)

All virtual server I/O will be concentrated onto the SAN A resilient storage subsystem will be required to ensure that the availability

of the virtual server environment.

The IBM N Series storage subsystem provides hardware and software that

provides significant advantages when used in a virtualised server environment:

IBM N Series FlexVol technology enables you to create multiple flexiblevolumes on a large pool of disks, aggregate I/O across all physical disks on

NFS, iSCSI or Fibre Channel. You can dynamically allocate storage and

add storage capacity as needed without downtime.

IBM N Series FlexClone provides instant clones of VMs without impactingserver resources and requiring additional storage capacity. This allows youto take copies of production virtual servers for testing, validation and

development


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IBM N Series Snapshot allows VMware users to make fast and space-efficient backup copies of active data with negligible performance and

storage overhead.

IBM N Series SnapMirror protects data and accelerates recovery, byproviding a simple, efficient way to replicate data between systems inmultiple locations using multi-transport (IP and FC) and frequency choice(synchronous, semi-synchronous, and asynchronous) options while only

transferring changed blocks.

IBM N Series Raid-DP (Double Parity) offers significantly more protectionthan single parity schemes (including RAID 5 and RAID 4), with zero to

minimal cost and performance impact. Compared to RAID 1 (mirroring),

RAID-DP offers equivalent data protection against double disk failure at a

fraction of the cost of mirroring. Compared to RAID 6, RAID-DP offers

better performance and ease of use.

The IBM N Series storage system provides a unified storage solution that

incorporates data management, snapshots, real-time backup and disk-to-disk

server backup. This simplifies the management of the vital storage component

of a virtual infrastructure. The IBM N Series is ideally suited to a virtual server

environment.

Of those companies

articipating in the 2001

Cost of Downtime Survey:

46% said each hourof downtime would

cost their companies

up to $50k

28% said each hourwould cost between

$51K and $250K

18% said each hourwould cost between

$251K and $1million

8% said it would costtheir companies more

than $1million per

hour.


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Virtual Server Backup and Recovery

Backing-up and ensuring that the backups are recoverable for large numbers of

virtual servers can be a difficult task. The task can be more difficult because of

the need to ensure that backup I/O does not affect production I/O resources.

Multiple modes of backup mirroring, point in time snapshots, offsite point in

time snapshots can be extended to all virtual servers and ensure recovery.

Existing Server Backup IBM N Series Comprehensive Server

Backup Model

Using the IBM N Series in a virtual server environment enables you to

implement a variety of backup and recovery approaches and techniques across

the entire virtual infrastructure seamlessly using one common interface and tool.

Because backups are disk-based, they are directly recoverable.

IBM N Series Snapshots do not result in any data movement and have any

impact on I/O, unlike the type of Snapshots available for other storage systems.

Therefore they are ideally suited for use in a virtual server environment.

Industry Standard Snapshot Model IBM N Series Snapshot Model

SnapVault software can be used to move SnapShots to a separate storage

location to act as a disk-to-disk backup.

Snapshots can be restored using SnapRestore software.

The N Series solution can support thousands of snapshots. Unlike other storagesubsystems, the N Series does not suffer any performance degradation. The

At what point is the

survival of your

company at risk?

40% said 72hours

21% said 48hours

15% said 24hours

8% said 8 hours9% said 4 hours

3% said 1 hour 4% said within

the hour

Cost of Downtime

Survey Results,2001


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performance impact of snapshots using other hardware platforms can involve a

60% or greater reduction in I/O performance.

With the IBM N Series, multiple separate snapshot schedules or policies can be

maintained, such as hourly snapshots retained for several days, daily snapshots

retained for several weeks, weekly snapshots retained for several months and soon.

IBM N Series SnapMirror

SnapMirror provides simple, flexible, and cost-effective replication software for

disaster recovery and data distribution.

SnapMirror can replicate virtual servers from one virtual infrastructure to

another to facilitate very rapid recovery and business continuity.

Exceptionally powerful, yet easy to implement and manage, IBM N SeriesSnapMirror software combines disaster recovery and data distribution in a

streamlined solution that supports today's global enterprises. SnapMirror is avery cost-effective solution with efficient storage and network bandwidth

utilisation, and provides additional value by enabling you to put the DR site to

active business use.

SnapMirror offers a straightforward set-up that you can easily replicate across

all your IBM N Series storage systems. Once installed, SnapMirror requires

minimal management, and SnapManager software ensures effortless replication

of application-consistent snapshots.

SnapMirror can mirror data from FC storage to ATA storage, reducing storagecosts. To reduce network usage, SnapMirror works with Snapshots to send only

changed data blocks to the disaster recovery storage.

SnapMirror enables space-efficient copies to be created on the disaster recoverystorage for other uses such as testing, development, and quality assurance,

without affecting the production system. SnapMirror also enables centralised

backup of data to tape from multiple data centres, reducing investment in tape

infrastructure as well as offloading the production system from tape backups.

IBM N Series FlexVol and FlexClone

FlexVol volumes are virtual dynamic storage entities that can grow and shrink

without being constrained by the underlying physical storage.

FlexClone uses ShapShot technology to create writable clones of FlexVol

volumes. Clones can be created nearly instantaneously and with little I/O and

storage overhead. FlexClone technology can be used to create copies of

production systems for testing, validation and development.

IBM N Series RAID Double Parity

IBM Storage System N series introduces double-parity RAID, named RAID-DP. This section provides an overview of RAID-DP and how it dramatically

increases data fault tolerance from various disk failure scenarios. Other key


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areas covered include how much RAID-DP costs, special hardware

requirements, and converting from existing RAID4-based volumes to RAID-

DP. This document presents a double-disk failure recovery scenario to show

how RAID-DP both allows the volume to continue serving data and recreates

data lost on the two failed disks.

Traditional single-parity RAID offers adequate protection against a single

event, which could be either a complete disk failure or a bit error during a read.

In either event, data is recreated using both parity and data remaining on

unaffected disks in the array or volume. If the event is a read error, then

recreating data happens almost instantaneously, and the array or volume

remains in an online mode. However, if a disk fails, then all data lost on it has

to be recreated, and the array or volume will remain in a vulnerable degraded

mode until data has been reconstructed onto a spare disk. It is in degraded

mode that traditional single-parity RAID shows its protection capabilities have

not kept up with modern disk architectures. RAID Double Parity significantly

increases the fault tolerance from failed disk drives over traditional RAID.

IBM System Storage N series uses a new type of RAID protection named

RAID-DP. RAID-DP stands for RAID Double Parity, and it significantly

increases the fault tolerance from failed disk drives over traditional RAID.

When all relevant numbers are plugged into the standard mean time to data

loss (MTTDL) formula for RAID-DP versus single-parity RAID, RAID-DP is

more reliable on the same underlying disk drives. With this reliability, RAID-

DP approaches RAID1 mirroring for fault tolerance, but at RAID4 pricing.

RAID-DP offers businesses the most compelling total cost of ownership storage

option without putting their data at an increased risk.

Conclusion

An effective storage platform is essential to the successful implementation and

operation of a virtualised server infrastructure.

Server virtualisation requires high-performing central storage. With virtualised

servers data is moved from local to central storage. The design and operation of

the storage component becomes of critical importance. This is particularly true

for organisations wishing to take advantage of high availability, centralised

backup and business continuity and disaster recovery features of server

virtualisation.

IBM storage is ideally suited for use in a virtualised server environment because

High Performance IBM storage solutions offer consistent high performance

with no performance degradation when taking system

snapshot.

Instantaneous Backups With Snapshot technology, you can make instantaneous,

consistent backup copies of active data with negligible

Streamline Storage

Allocation toVirtual Machines

VMware administrators can supply storage to virtual

machines in seconds while achieving the highest level ofstorage utilisation.


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Thin Provisioning IBM storage systems offer powerful, flexible provisioning

capabilities that give IT storage specialists the ability to

lower cost while meeting capacity, utilisation, and

performance requirements.

Raid-DP RAID-DP offers significantly more protection than singleparity schemes (including RAID 5 and RAID 4), with zero

to minimal cost and performance impact. Compared to

RAID 1 (mirroring), RAID-DP offers equivalent data

protection against double disk failure at a fraction of the

cost of mirroring. Compared to RAID 6, RAID-DP offers

better performance and ease of use.

Disaster Recovery You can protect data and speed recovery using SnapMirror.

SnapMirror provides a simple, efficient way to replicate

data between systems in multiple locations using multi-

transport (IP and FC) and frequency choice (sync, semi-

sync, and async) options while transferring only changed

blocks. In the event of a disaster, a remote site can use the

SnapMirror copy of the data to restart critical virtual

servers with minimal disruption to ongoing operations.

Flexibility IBM storage solutions give you the ultimate in flexibility by

enabling you to choose iSCSI, FCP, or NFS connectivity

within a single storage platform. IBM systems can also mix

drive types within a single system so that you can tier your

virtual machines (VMs) within a single architecture, giving

users flexibility and investment protection.

Efficient Cloning of

VMs

Using the FlexClone tool, you can instantly create VMs

without consuming any additional physical storage. These

clones can be used for production and test and development

environments.


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For more information, please contact:

[email protected]

Whitepaper - Server Virtual is at Ion and Storage Management

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