Administrator Guide

Requirement Description
QoS definitions Quality of Service (QoS) definitions must be defined on the primary and secondary Storage Centers.
Server
• MPIO must be enabled on the server to prevent I/O interruption.
Live Volume Types
Live Volumes can be created using asynchronous replication or synchronous replication.
Storage Center version 7.3 and later provides support for ALUA optimization of Live Volumes.
Live Volume ALUA allows the Storage Center to report path priority to servers for Live Volumes. The servers can make use of this path
priority to prefer sending I/O to the better performing paths. In practice, I/O is directed towards the paths of the Primary Live Volume.
In Storage Manager, the Summary tab of a Live Volume reports whether a Live Volume is ALUA optimized. If Live Volumes exist that are
not ALUA optimized, Storage Manager displays an alert and provides a link to a guided process to update Live Volumes to ALUA
optimized.
Related concepts
Asynchronous Replication
Synchronous Replication
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 IO 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.
Storage Center Replications and Live Volumes
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