Hardware manual

Group Administration Volume replication
12–7
See the PS Series Release Notes for replication limits.
2. If you did not already configure the groups as replication partners:
a. Log in to the primary group and configure the second
ary group as a replication partner.
b. Log in to the secondary group and configure the primary group as a replication partner. Make sure you
delegate the correct amount of space to the primary group for storing replicas of primary group volumes.
If you already configured the groups as replication partners, ch
eck the secondary group space that is delegated
to the primary group and increase it, if necessary.
See About replication partners on pa
ge 12-16.
3. On the primary group, configure the volume for replicat
ion, specifying the appropriate replication space
values. See Configuring a volume for replication on page 1
2-25.
4. On the primary group, replicate the volume. See Cr
eating a replica on page 12-28.
You can set up a schedule to create replicas on a regular basis. See Using schedules to create replicas on page
12-
30.
5. Monitor each replication operation and make sure
it is successful. See Displaying replication activity and
replicas for a volume on pa
ge 12-28.
If the replication operation is not successful, identify a
nd correct the problem. For example, you might need to
increase network bandwidth or increase replication space.
6. Monitor the number of replicas and replication space usa
ge over time. The goal is to keep a specific number of
replicas without wasting replication space.
If replicas are deleted before you reach the number of replicas you want to keep, you might want
to increase the
replica reserve percentage for the volume.
If you are keeping an excessive number of replicas, you might want to de
crease the replica reserve percentage
for the volume.
To recover volume data from replicas, see Data recovery on pa
ge 13-1.
About replication space
Volume replication between partners requires space on the primary group (volume location) and on the secondary
group (replica location):
• Local replication reserve. Eac
h volume requires primary group space for use during replication and,
optionally, for storing the failback snapshot. See About local replication reserve on
page 12-8.
• Delegated space. T
o provide space for storing replicas, the secondary group delegates space to the primary
group. All primary group volumes that you replicate to the secondary group share the delegated space.
Each volume is assigned a portion of delegated space, calle
d the replica reserve. The replica reserve for a
volume limits the number of replicas you can keep. When replica reserve is consumed, the oldest replicas are
deleted to free space for new replicas.