Hardware manual

12–1
12 Volume replication
Vo l u m e replication between different groups provides protection against data loss. If a volume is destroyed, you
can fail over to the recovery group and recover data from a replica. Users can then resume access to the recovery
volume. When the original volume becomes available, you can failback to the original group.
About replication
An effective data recovery solution must help you correct day-to-day mistakes (such as when users erroneously
delete files or volumes), computer viruses, and site disasters.
Some solutions are time-consuming and
involve backing up data and manually transporting the backups to a
different physical location. Other solutions rely on expensive hardware and the ability to copy data over long
distances, which can decrease application performance.
Using the replication technology pro
vided by PS Series firmware, you can copy volume data from one group to
another, protecting the data from a variety of failures, ranging from the destruction of a volume to a complete site
disaster, with no effect on data availability or performance.
You can use PS Series replication functionality alone or in
conjunction with Auto-Snapshot Manager (for Windows
or VMware) or Storage Replication Adaptor for VMware Site Recovery Manager. See the product documentation
for details.
About replicas
Similar to a snapshot, a replica represents the contents of the volume at the time the replica was created. Each
replicated volume has a replica set, which is the set of replicas created over time.
You can create replicas of individual volumes or volume collections. Y
ou can create replicas at the current time, or
you can set up a schedule.
Individual replicas are identified by th
e date and time that the replication operation started.
The replica set name is based on the volume name and includes
a dot-number extension to ensure that all replica set
names are unique, in case two different partners replicate volumes with the same name to the same group. The
number in the extension reflects the order that each partner was configured as a replication partner to the group. For
example, all replica sets from the first configured partner have a dot-1 extension (such as,
dbase.1). Replica sets
from the next configured partner have a dot-2 extension (such as,
dbase.2).
A volume and its replica set are always stored in different gro
ups connected by a robust network link. Separating
the groups geographically protects volume data in the event of a complete site disaster.