Administrator Guide

Table Of Contents
Managed Replications for Live Volumes
A managed replication allows you to replicate a primary Live Volume to a third Storage Center, protecting against data loss in
the event that the site where the primary and secondary Storage Centers are located goes down. When a Live Volume swap
role occurs, the managed replication follows the primary volume to the other Storage Center.
Supported Live Volume with Managed Replication Topologies
Three specific combinations of Live Volume type and managed replication type are supported. The following table lists the
supported combinations.
Live Volume Type Managed Replication Type
Asynchronous Synchronous
Asynchronous Asynchronous
Synchronous Asynchronous
Live Volume with Managed Replication Example Configuration
The following examples show how a managed replication behaves before and after a Live Volume swap role.
Live Volume behavior: When a server near the primary Storage Center sends an IO request that modifies the primary
volume, the changes to the primary Live Volume are replicated to the secondary Storage Center over Fibre Channel or
iSCSI. When a server near the secondary Storage Center sends an IO request to the secondary Live Volume, the secondary
Storage Center forwards the IO request to the primary volume on the primary Storage Center. These changes to the primary
volume are ultimately replicated to the secondary volume.
Managed replication behavior: The changes to the primary Live Volume are replicated to the third Storage Center over
Fibre Channel or iSCSI. When a Live Volume swap role occurs, the managed replication follows the primary volume to the
other Storage Center.
Managed Replication Before Live Volume Swap Role
In the following diagram, the primary Storage Center is on the left and the secondary Storage Center is located on the right.
Figure 53. Live Volume with Managed Replication Example Configuration
1.
Server 2. Server IO request to primary volume over Fibre Channel or
iSCSI
3. Primary volume (Live Volume and managed replication) 4. Live Volume replication over Fibre Channel or iSCSI
5. Secondary volume (Live Volume) 6. Server IO request to secondary volume (forwarded to
primary Storage Center by secondary Storage Center)
7. Server 8. Destination volume (managed replication)
9. Managed replication over Fibre Channel or iSCSI
524 Storage Center Replications and Live Volumes