Example scenario
The following example illustrates one process for synchronizing data. Remember that synchronization
is optional.
Table 7 Timeline of failover
Time
1:00 p.m.
1:10 p.m.
1:30 p.m.
1:33 p.m.
2:00 p.m.
The following data needs to be synchronized once the primary volume is back online:
Original volume, which contains data from 1:00 to 1:30 p.m.
Acting primary volume which contains data from 1:33 to 2:00 p.m.
Returning operations to original primary site
After the original primary site is operational again, restore operations to that site. The steps to
restore operations depend upon the state of the original primary volume.
If the primary volume is working:
Synchronize the data between the acting primary volume and the restored primary volume
before returning the acting primary volume to its remote volume state.
If the primary volume is not available:
Create a new primary volume, synchronize the data with the acting primary volume, and then
return the acting primary volume to a remote volume.
Synchronizing the data between the acting primary volume and the original primary volume
Create snapshots that contain the data that you need to synchronize.
Table 8 Creating snapshots of data to synchronize
Action
1. Stop applications that are
accessing the volumes.
2. Make a snapshot of the
original volume.
3. Make the acting primary
volume into the remote
volume. This automatically
creates a snapshot of the
acting primary volume.
Synchronize the data
Event
Regular hourly scheduled remote
snapshot starts.
Remote copy finishes.
Primary volume goes offline.
Scripted failover causes remote volume
to become the acting primary volume.
Original primary volume comes back
online.
Volumes and snapshots on
primary management group
O r i g P r i m a r y V o l _ 1 O r i g P r i m a r y S S _ 1
What happens
RemoteSS_1 creates in remote
management group.
Copying is complete.
OrigPrimaryVol_1 is offline.
ActPrimaryVol_1 becomes primary
and active, and usable to application
server.
OrigPrimaryVol_1 is online.
Volumes and snapshots on
remote management group
Remotevol_1ActPrimarySS_1
Resuming production after failover
What this step accomplishes
Creates a snapshot of the
original primary volume that
includes the data from 1:00
- 1:30 p.m.
Returns the remote
management group to its
original configuration. In
addition, you capture the
1:33 to 2:00 p.m. data.
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