Administrator Guide

Live Volume Before Swap Role
In the following diagram, the primary Storage Center is on the left and the secondary Storage Center is on the right.
Figure 47. Example Live Volume Configuration
1. Server 2. Server IO request to primary volume over Fibre Channel or iSCSI
3. Primary volume 4. Live Volume replication over Fibre Channel or iSCSI
5. Secondary volume 6. Server IO request to secondary volume (forwarded to primary
Storage Center by secondary Storage Center)
7. Server
Live Volume After Swap Role
In the following diagram, a role swap has occurred so the secondary Storage Center is on the left and the primary Storage Center is on the
right.
Figure 48. Example Live Volume Configuration After Swap Role
1.
Server 2. Server IO request to secondary volume (forwarded to primary
Storage Center by secondary Storage Center)
3. Secondary volume 4. Live Volume replication over Fibre Channel or iSCSI
5. Primary volume 6. Server IO request to primary volume over Fibre Channel or iSCSI
7. Server
Automatic Swap Role for Live Volumes
Live Volumes can be configured to swap primary and secondary volumes automatically when certain conditions are met to avoid situations
in which the secondary volume receives more IO than the primary volume.
Attributes that Control Swap Role Behavior
When automatic swap role is enabled, the following limits determine when a role swap occurs.
Swap Role Limit
Description
Min Amount Before Swap Specifies the minimum amount of storage space that must be written to
the Live Volume on the secondary Storage Center before the roles can be
swapped
494 Storage Center Replications and Live Volumes