Administrator Guide

Table Of Contents
Synchronous Replication on page 501
Live Volume Icon
The Live Volume icon indicates Live Volumes on the Storage tab of the Storage view to differentiate it from regular volumes
and replicated volumes.
NOTE: To determine whether a Live Volume is primary or secondary from the Storage tab, select the Live Volume, then
review the Live Volume Attributes section under the Summary subtab.
Live Volume Roles
There are two roles for Live Volumes: primary and secondary. These roles determine the direction of the replication, and they
can be swapped automatically or manually. Write performance is reduced for the secondary volume because the primary volume
must also acknowledge these writes.
Live Volume Role Description
Primary
Hosts the primary volume, which is like the source volume for a conventional replication
Replicates the primary volume to the secondary volume
Processes all I/O from both the primary and secondary site
Secondary
Hosts the secondary volume
Accepts I/O for the Live Volume and routes it to the primary volume on the primary
Storage Center
Live Volume Roles Example
In the following examples, a server sends an IO request that modifies the primary volume. The changes to the primary volume
are replicated to the secondary Storage Center over Fibre Channel or iSCSI. When a server connected to the secondary Storage
Center sends an IO request to the secondary volume, the secondary Storage Center forwards the IO request to the primary
volume on the primary Storage Center.
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
Storage Center Replications and Live Volumes 519