Building Disaster Recovery Serviceguard Solutions Using Metrocluster with Continuous Access for P9000 and XP A.11.00

Failback

If the primary site is restored after a failover to the recovery site, you may want to fail back the

package to the primary site. Manually resync the data from the recovery site to the primary site

and wait for the resynchronization to complete. Before failing back the package from the recovery

site to the primary site, run the cmdrprev command on the primary site nodes to preview the data

replication storage failover. For more information about the cmdrprev command, see “Data

replication storage failover preview” (page 51).

Halt the package on the recovery site, and restart it on the primary site. Metrocluster performs a

failover of the storage, which returns the PVOL status to the disks in the primary site.

Maintaining a cluster that uses Metrocluster with Continuous Access for P9000 and

In normal operation, the Metrocluster with Continuous Access for P9000 and XP starts like any

other cluster, runs and halts packages in the same way as a standard cluster. However, startup

time for packages might be considerably slower because of the, must verify, disk status on both

disk arrays.

While the cluster is running, performing manual “changes of state” for devices on the P9000 or

XP Series disk array can cause unexpected pair states for the device group preventing successful

package failover. In general, manual “changes of state” must not be performed while the package

and the cluster is running.

NOTE: However manual changes can be made when data protection must be restored manually

for a device group. For Example, if a package starts up with data replication suspended, a user

can perform a pairresync command to re-establish data replication while the package is still

running.

Viewing the progress of copy operations

While a copy is in progress between P9000 or XP arrays (that is, the volumes are in a COPY state),

the progress of the copy can be viewed by monitoring the % column in the output of the

pairdisplay command:

# pairdisplay -g pkgB -fc -CLI

Group PairVol L/R Port# TID LU Seq# LDEV# P/S Status Fence % P-LDEV# M

pkgB pkgD-disk0 L CL1-C 0 3 35422 463 P-VOL COPY NEVER 79 460 -

pkgB pkgD-disk0 R CL1-F 0 3 35663 3 S-VOL COPY NEVER - 0 -

This display shows that 79% of a current copy operation has completed. Synchronous fence levels

(NEVER and DATA) show 100% in this column when the volumes are in a PAIR state.

Viewing side file size

If you are using asynchronous data replication, you can see the current size of the side file when

the volumes are in a PAIR state by using the pairdisplay command. The following output,

obtained during normal cluster operation, shows the percentage of the side file that is full:

# pairdisplay -g pkgB -fc -CLI

Group PairVol L/R Port# TID LU Seq# LDEV# P/S Status Fence % P-LDEV# M

pkgB pkgD-disk0 L CL1-C 0 3 35422 463 P-VOL PAIR ASYNC 35 3 -

pkgB pkgD-disk0 R CL1-F 0 3 35663 3 S-VOL PAIR ASYNC 0 463 -

This output shows that 35% of the side file is full.

When volumes are in a COPY state, the % column shows the progress of the copying between the

P9000 or XP frames, until it reaches 100%, at which point the display reverts to showing the side

file usage in the PAIR state.

70 Administering Metrocluster