HP LeftHand P4000 Virtual SAN Appliance Software - Manual (Page 29)

Example scenario
The following example illustrates one process for synchronizing data. Remember that synchronization
is optional.
Table 7 Timeline of failover
What happens Event Time
RemoteSS_1 creates in remote
management group.
Regular hourly scheduled remote
snapshot starts. 1:00 p.m.
Copying is complete. Remote copy finishes. 1:10 p.m.
OrigPrimaryVol_1 is offline. Primary volume goes offline. 1:30 p.m.
ActPrimaryVol_1 becomes primary
and active, and usable to application
server.
Scripted failover causes remote volume
to become the acting primary volume. 1:33 p.m.
OrigPrimaryVol_1 is online. Original primary volume comes back
online. 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
What this step accomplishes Volumes and snapshots on
remote management group Volumes and snapshots on
primary management group Action
1. Stop applications that are
accessing the volumes.
Creates a snapshot of the
original primary volume that OrigPrimaryVol_1OrigPrimarySS_1 2. Make a snapshot of the
original volume.
includes the data from 1:00
- 1:30 p.m.
Returns the remote
management group to its Remotevol_1ActPrimarySS_1 3. Make the acting primary
volume into the remote
original configuration. In volume. This automatically
addition, you capture the
1:33 to 2:00 p.m. data. creates a snapshot of the
acting primary volume.
Synchronize the data
Resuming production after failover 29