Administrator Guide

Table Of Contents
Storage Center Live Volumes
A Live Volume is a replicating volume that can be mapped and active on a source and destination Storage Center at the same
time. While both Storage Centers can accept writes, when a server writes to the destination volume, the writes are redirected
to the source volume before being replicated back to the destination.
Unlike replicated volumes, Live Volume primary and secondary volumes share the same volume identity, which means that
servers recognize the primary and secondary volumes as the same volume.
NOTE: The Live Volume feature is not supported on storage systems with front-end SAS connectivity.
Behavior of Volume QoS Settings in Live Volume Operations
Any Volume or Replication QoS settings that have been defined are enforced only on the primary side of a Live Volume. If the
secondary Storage Center becomes primary Storage Center as the result of a swap or DR Activate, the Volume QoS attributes
and Replication QoS settings from that Storage Center are enforced. This behavior differs from how Volume QoS settings are
enforced for a replication.
Live Volume Requirements
To create Live Volumes, the requirements listed in the following table must be met.
Requirement Description
Storage Center version The primary and secondary Storage Centers must be running the same version of Storage
Center software.
Storage Center license The primary and secondary Storage Centers must be licensed for Live Volume.
Storage Manager
configuration
The primary and secondary Storage Centers must be added to Storage Manager.
NOTE: A Live Volume must use the same LUN number on both the primary and secondary
Storage Centers.
Storage Center
communication
The primary and secondary Storage Centers must be connected using Fibre Channel or iSCSI,
and each Storage Center must be defined on the other Storage Center.
On the primary Storage Center, the secondary Storage Center must be defined as a
remote Storage Center.
On the secondary Storage Center, the primary Storage Center must be defined as a
remote Storage Center.
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 on page 501
518
Storage Center Replications and Live Volumes