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Disk Based Disaster Recovery & Data Replication Solutions

Gavin ColeStorage Consultant SEE

Agenda

Planning for a Disaster Using Local Copies for Protection Using Remote Mirroring for Protection Conclusion

Agenda

Planning for a Disaster Using Local Copies for Protection Using Remote Mirroring for Protection Conclusion

Disaster

Jon William Toigo

Chairman, Data Management Institute

2005

any interruption in the normal access to a valid set of data used by applications and end users to execute mission critical business processes for an unacceptable period of time.

Hardware 44%

Operator 32%

Software 14%

Virus 7%

Disaster 3%

Causes of Data Loss 2002

Source: Ontrack Data Report 2007

Hardware 59% Operator 26%

Software 9%

Virus 2%Disaster 2%other 2%

Causes of Data Loss 2006

Source: Ontrack Data Report 2007

The threat of data loss can’t be ignored

• Risks:> High cost of data loss and downtime> Insufficient data recovery plans and procedures > 70% of businesses fail after major data loss > Recovery overextends limited staffs and financial

resources

• Needs:> High availability and fast data recovery > Seamless integration with existing IT infrastructures > Interoperability with current and future storage and

computing systems

The Cost of Downtime• Forrester Consulting Interviewed 138 companies• Estimated cost of 1 hour downtime

> Less than $10,000 / hr – 25%> $10,000 to $100,000 / hr – 33%> $100,000 to $500,000 – 25%> $500,000 to $1 million – 13%> Greater than $1 million – 4%

• 67% - could not estimate the financial cost of downtime

Disaster

Key definitions

Last safe

Backup

Resumption

of normal

business

Recovery Point Objective (RPO)

The time between the last safe backup and the point of

time of the disaster

Recovery Time Objective (RTO)

The time elapsed from when the disaster occurred to the

resumption of normal business activities

Business Continuity

• Planning to never go down• Always have access to information• Needs more than a good data recovery strategy• A disaster can be something as simple as a deleted

file• Use disk duplication strategies

> Mirroring> Snapshot> Remote replication

Seconds

MinutesHours

Days

Regional Disaster

Local Disaster

Operator error

Hardware failure

Application

Department

Data Center

Enterprise

RiskDisruption

Scale

Complete data protection requires personalized and practical solutions

Business goals

Threats

Budget realities

Existing assets

Seven Key Planning Steps

1. Business impact assessment How long can I live without data?

2. Discovery What data do I need first?

3. Budget What is my data worth?

4. Role-based teams Who are the key people?

5. Data protection How do I protect what I need?

6. Logistics What are the physical requirements?

7. Testing Will my plan work?

Agenda

Planning for a Disaster Using Local Copies for Protection Using Remote Mirroring for Protection Conclusion

Volume Copy TermsComplete point in time replication of one Volume (source)

to another (target) within a Storage Subsystem

Source = Volume that accepts host I/O and stores application data

Target = Volume that maintains a copy of the data from the source

Target or Copy or Clone

Copy Pair

How Volume Copy Works

SnapshotSnapshot- a logical point-in-- a logical point-in-time image of time image of another volume. another volume. Logical equivalent of Logical equivalent of a complete physical a complete physical copycopy

Logical Disk Space

Snapshot Terms

Storage SystemStorage System

Base Base VolumeVolume- the volume from - the volume from which the which the Snapshot will be Snapshot will be createdcreated

Physical Disk Space

Repository Repository – stores original – stores original blocks from Base blocks from Base before they are before they are overwritten with overwritten with new datanew data

Physical Disk Space

• A point-in-time (PiT) image of a volume > Logical equivalent of a physical copy

Snapshot Flow Chart

Using Volume Copy and Snapshot together

Copying the Snapshot creates a full PiT clone copy while I/O continues to base volume (LUN)

Agenda

Planning for a Disaster Using Local Copies for Protection Using Remote Mirroring for Protection Conclusion

Remote Volume Mirroring

• Ongoing, real-time replication of a volume from one storage system to another

Remote Volume Mirroring Components

Primary volume: accepts read and write host I/OSecondary volume: accepts read host I/O. accepts remote writes of data from controller owner of Primary

volume.

Primary Secondary Secondary Primary

Remote Volume Mirroring Components

Mirror Repository volume: Stores mirroring data, such as info about remote writes that have not completed

Primary Secondary Secondary Primary

Mirror

Repositories

Mirror

Repositories

Mirror Pairs

V1 -> V1M

V2 -> V2M

V3 -> V3M

Synchronous Replication

• The primary disk system acknowledges a host write when the data has been successfully mirrored

• Primary benefit> Ensures remote data is an exact replicate of the local

data• Note: only effective for campus area replication

• Primary benefits> Reduces impact of latency when replicating over longer distances

> Provides performance improvement – compared to synchronous – for primary site I/O (disk system and application)

> Enables effective replication over longer distances (WAN)

• Allows the primary disk system to acknowledge a host write request before the data has been successfully mirrored

Asynchronous Write Mode

• Write operations to the secondary disk system matches I/O completion order on the local disk system > Also referred to as a consistency group

• Primary benefit> Maintains data integrity in multi-LUN applications (databases)

by eliminating out-of-order updates at the remote side that can cause logical corruption

Preserved Write Order

Remote Volume Mirroring Mirror Management• Role Reversal (from secondary to primary or vice

versa) is user-initiated> If primary is also base volume for snapshots, role

reversal will cause associated snapshots to fail> It is possible to force role change for the local volume

if communication to the remote volume is down> Used in disaster recovery scenarios

> Can prepare by mapping secondary volumes to hosts using Storage Partitions before they are promoted

DR / HA Architecture

Cluster 1

Cluster 2

Volume 3 replication

Volume 1 & 2 replication

Site A Site B

* M = mirror* M = mirror

Architecture Description Site A and Site B each contain a copy of critical data Critical data is copied in real time using the disk controllers

minimal impact on server processing power OS and key applications are clustered across both sites

If either site fails application transparently fails over to remote Customers notices minimal disruption

2 way Disaster Protection Cluster 1 uses volume V1 and V2 – primary business is at Site A,

Mirrored to Site B for protection

Cluster 2 uses volume V3 - primary business is at Site B, Mirrored to Site A for protection

Sites are connected by Fibre Channel network for performance Could be connected by long distance IP network – will be

performance impact on replication.

Agenda

Planning for a Disaster Using Local Copies for Protection Using Remote Mirroring for Protection Conclusion

Could you survive a disaster?

• 35% of companies have a plan• 60% of plans are never tested• Half the companies that suffer losses never

recover• $10 – $50 K per MB to re-create data

Seven Key Planning Steps

1. Business impact assessment How long can I live without data?

2. Discovery What data do I need first?

3. Budget What is my data worth?

4. Role-based teams Who are the key people?

5. Data protection How do I protect what I need?

6. Logistics What are the physical requirements?

7. Testing Will my plan work?

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Thank You

Gavin Cole

gavin.cole@sun.com

+33 6 70 72 99 53

Disaster Recovery Planning