Data Replication manager with Compaq Tru64 UNIX Logical Storage Manager

Augmented Failover, Failback, and Role Reversal Procedures
16 Application Notes – Data Replication Manager with HP Tru64 UNIX Logical Storage Manager
Augmented Failover, Failback, and Role Reversal Procedures
This section covers the following topics:
• All Procedures Description, page 16
• Augmented Procedures with Scripts, page 16
• Augmented Procedures with Command Line Interpreter, page 18
When LSM is used to manage your storage units, special handling of the volumes is required before
and after the failover, failback, and role reversal procedures. Several extra steps are necessary for
failover, failback and role reversal. Which steps are used depends on whether you are using the HP
DRM Scripting Kit scripts or the command line interpreter (CLI) commands.
If you are using the HP DRM Scripting Kit scripts, follow the steps below under the heading
“Augmented Procedures with Scripts.” If you are not using scripts, use the steps under the section
heading “Augmented Procedures with Command Line Interpreter.”
All Procedures Description
Before removing host access to the storage units, LSM access must be removed. To cleanly remove
LSM access, unmount all of the volumes under a disk group, then deport the disk group. This allows
the host access to be disabled without unintended consequences.
NOTE: If a disk group is deported, and there is an entry in the /etc/fstab file to mount a volume from
that disk group upon host boot, then the host gives an error during the boot sequence. The error is
given because the host cannot find the volume. To prevent this from occurring, comment out the line for
that particular volume in the /etc/fstab file before rebooting.
After host access is enabled from the controllers, place the volumes back under the control of LSM. To
give LSM access to the volume, first import the disk group, then mount it. Once this is done, the I/O
operations can restart.
The procedures for an unplanned failover are different from those for a planned failover. When an
unplanned failover occurs, and the volume was not deported from the initiator, the volume still has the
initiator host label on it. To allow remote access to the volume, import the volume with a forced import
and clear host ID flags. Start and mount the volume, and begin I/O processes.
Augmented Procedures with Scripts
If you are using scripts to perform failover, failback, and resumption of operation procedures found in
the hp StorageWorks Data Replication Manager HSG80 ACS Version 8.7P Scripting User Guide, Part
Number EK-DRMSC-OA. D01, augment those procedures with the following steps:
Chapter 6: Unplanned Site Failover with Full Failback Procedure
• On page 6-3, perform the following additional target site tasks at the end of the
HP Tru64 UNIX-specific operations in step 3b:
Import the disk groups using the forced import, with the clear host ID flag. Start the volumes,
if not already started, then mount the volumes.
• On page 6-6, perform the following additional target site tasks at the end of step 4:
Unmount the volumes, then deport the disk groups.