Advanced Site Recovery -- Technical Briefing
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1© 2009 DataCore Software Corp. — All rights reserved © 2009 DataCore Software Corp
Advanced Site Recovery (ASR)Advanced Site Recovery (ASR)
Technical Briefing
Advanced Site Recovery (ASR)Advanced Site Recovery (ASR)
Technical Briefing
2© 2009 DataCore Software Corp. — All rights reserved
TopicsTopics
Why prepare for Site Recovery?
Traditional approaches
Motivation for splitting Disaster Recovery sites
ASR unique attributes
How it works
Scenarios
Combining HA with DR
ASR Look & Feel
Cut over procedure
Central site restoration
3© 2009 DataCore Software Corp. — All rights reserved
Why Prepare for Site Recovery?Why Prepare for Site Recovery?
Infrastructure failures Power, air conditioning, external network, etc.
Equipment maintenance HW/SW upgrade, repairs, reconfiguration
Facility closuresWater leaks, fire, building construction/move, security lockdown
Natural disastersFloods, earthquakes, storms, etc.
4© 2009 DataCore Software Corp. — All rights reserved
Regionally Distributed LocationsRegionally Distributed Locations
VM
Branch x
Internet
Central IT site
5© 2009 DataCore Software Corp. — All rights reserved
But, Single Disaster Recovery Site?But, Single Disaster Recovery Site?
DR Site
RemoteReplication
Central IT site
• Fat pipe
• Larger real-estate• More machines• Wasted resources
• High-end Storage• Identical systems
6© 2009 DataCore Software Corp. — All rights reserved
Low Cost Alternative: 1-to-Many DRLow Cost Alternative: 1-to-Many DR
VMVM
VMVM
Central IT site
HA
VM
VM
DR Site x
RemoteReplication
StorageVirtualization
• Thin pipes
StorageVirtualization
7© 2009 DataCore Software Corp. — All rights reserved
ASR Unique AttributesASR Unique Attributes
Take advantage of branch office locations
Distribute DR responsibilities• One central site protected by 2 or more smaller locations• Viable with lower speed WAN circuits• Standard Windows Servers virtualize storage using
Bi-directional replication
No application dependencies
No virtual machine dependencies
No host agents
8© 2009 DataCore Software Corp. — All rights reserved
Combining HA with DRCombining HA with DR
VMVM
VMVM
Central IT site
HARemote
Replication
9© 2009 DataCore Software Corp. — All rights reserved
ASR – How it WorksASR – How it Works
LUN LUN
look-alike replicas
ASR creates look-alike LUN replicas
LUN replicas are completely identical
Apps / VSEs / VMs don't encounter any differences
Apps / VMs can be started in any location without modification
Central IT Site DR Site
Remote Replication
10© 2009 DataCore Software Corp. — All rights reserved
ASR Data FlowASR Data Flow
Central IT siteCentral IT site
PP SS
SSDRDR
L1L1
HA Optional
DS1
DS1-DR
HourlySnapshots
TransmiTransmit Queuet QueueTransmiTransmit Queuet QueueSync
Mirror
SyncMirror
Mapped(online)
Mapped(offline)
12
L2L2
Only torestore
TransmitQueue
Kept currentwith DR site
3DR Site xDR Site x
Internet
WAN
PPDRDR
11© 2009 DataCore Software Corp. — All rights reserved
Failover: Two ScenariosFailover: Two Scenarios
Controlled Scheduled cut over No data loss Minimally disruptive
When: Major site maintenance Danger anticipated
• Imminent ice storm• Hurricane• Flooding
Relocation / facility move
Uncontrolled No warning Some data loss
• Buffered changes & cachesnever transmitted
Crash-consistent system recovery
12© 2009 DataCore Software Corp. — All rights reserved
Cut Over ProcedureCut Over Procedure
Controlled Suspend I/Os Flush caches Flush source buffer Await synchronization Restart on remote end
Uncontrolled Restart on remote end
13© 2009 DataCore Software Corp. — All rights reserved
PP SS
Central Site RestorationCentral Site Restoration
Internet
WAN
Central IT siteCentral IT site
PP SS
L2L2
PPDRDR
DS1
DS1-DR
Restore
TransmitQueue
Updated fromDR site
SyncMirror
Mapped(offline)
Mapped(online)
12
DR Site xDR Site x
14© 2009 DataCore Software Corp. — All rights reserved
Restoring Central SiteRestoring Central Site
Controlled Suspend I/Os on remote DR
site Flush caches Flush source buffer Await synchronization of all
dependent volumes Apply changes to original
virtual disks
Uncontrolled Re-initialize
Repeat for each DR site
15© 2009 DataCore Software Corp. — All rights reserved
Handling Link OutagesHandling Link Outages
Elastic source buffer sized to accommodate2 to 3 day WAN disruption
Switches automatically to log mode when space is exhausted
• Track blocks changed during outage• Transmit latest block contents when link is restored
16© 2009 DataCore Software Corp. — All rights reserved
Why Intermediate SnapshotsWhy Intermediate Snapshots
Ensure point-in-time consistency across groups of volumes
Separate from asynchronous updates that travel independently
17© 2009 DataCore Software Corp. — All rights reserved
Coordinating Dependent VolumesCoordinating Dependent Volumes
Group operations• Single request drives simultaneous action
across groups of virtual disks• In-band markers trigger remote snapshots
Simplifies distributed updates
18© 2009 DataCore Software Corp. — All rights reserved
How is ASR Delivered?How is ASR Delivered?
ASR Option - $2K per “region”
Multi-day Implementation service• Performed by an ASR-authorized and trained DataCore solution provider
Authorized partner requirements• DCIE (SANsymphony)• Attend ASR training (1 day)
Prerequisites• SANsymphony nodes at each end• Inter-site IP connections
19© 2009 DataCore Software Corp. — All rights reserved
Key Features of DataCore’sKey Features of DataCore’sAdvanced Site Recovery solutionAdvanced Site Recovery solution
Fast• Keeps DR site
up to date
Automated Eliminates error prone,
manual steps
Universal• Works equally well for
virtual & physical servers or different applications
Distributed • Accounts for multiple
sites / branch locations
Bi-directional• Resume operation at
original location
Verifiable• Easy to regularly
test / confirm recovery
20© 2009 DataCore Software Corp. — All rights reserved
Questions ?????