User's Guide

1. Verify that all the nodes in DC1, DC2 and DC3 are up and running.
2. Start DC1-DC2 cluster if it is not running.
3. Start the RAID Manager instance on each node in DC1, DC2 and DC3.
4. Verify that all the Continuous Access links are up.
5. Halt the 3DC package if it is running on DC3.
6. Recover the latest data from DC3
7. Change the Cluster ID of all LVM and SLVM volume groups managed by the package. For
LVM volume groups, run the following commands from a node in the primary cluster to change
the cluster ID:
# vgchange -c n <vg_name>
# vgchange -c y <vg_name>
For SLVM volume groups, run the following commands from a node in the primary cluster to
change the cluster ID:
# vgchange -c n -S n <vg_name>
# vgchange -c y -S y <vg_name>
8. Enable the package on all nodes in the primary cluster.
9. Start the package on its primary node in the primary cluster.
Recovering the latest data from DC3
This section describes the recovery procedures for the following scenarios in a Three Data Center
environment.
• “MULTI-HOP-BI-LINK Data Recovery from DC3 to DC1” (page 467)
• “MULTI-TARGET-BI-LINK Data Recovery from DC3 to DC1” (page 469)
• “TRI-LINK Data Recovery from DC3 to DC1” (page 470)
Recovering the latest data from DC3, as described in Step 6 above, guarantees that before the
packages are run on DC1, the latest data from DC3 is replicated on to DC1. The process for this
may vary depending on whether the 3DC configuration uses either Multi-hop Bi-Link configuration
or Multi-target Bi-Link configuration or Tri-Link configuration. The next section lists the required
commands to perform this process, which correspond to both the configurations, and are relevant
only to the recovery process of the latest data from DC3 to DC1.
MULTI-HOP-BI-LINK Data Recovery from DC3 to DC1
The following describes the process to restart a package back to DC1 after the package fails over
to DC3:
1. Log on to any node at DC2 and perform the following:
a. Check the pair status of the dg12 device group:
# pairvolchk -g dg12 -s
b. If the local dg12 volume is in PVOL or SVOL-SSWS.
# pairsplit -g dg12
Go to Step 2
Or
c. If local dg12 volume is other than PVOL or SVOL-SSWS perform a SVOL takeover to
make the local volume SVOL-SSWS or PVOL
# horctakeover -g dg12 -S
Failback Scenarios 467