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RamDisc volume group recovery following a vgscan command... Introduction: This document describes a command line procedure that may be required
to recover RamDisc volume groups following the execution of the vgscan command.
The man page for the vgscan command states This command should be run only in the
event of a catastrophic error such as the deletion of the /etc/lvmtab file or the
mismatch of names of the physical volumes in the /etc/lvmtab file to the actual
physical volume path configuration. This command will re-construct /etc/lvmtab by
searching throughout the typical disk I/O of the system and find physical volumes
that belong to each volume group. However, the vgscan command is not aware of the
RamDisc devices belonging to RamDisc volume groups and does not include them in
the newly created /etc/lvmtab file. Based on how your RamDisc is configured, the
following describes the process of restoring RamDisc volume groups to the system.
Please contact RamDisc technical support if you have any questions or concerns
before attempting any file edits or scripted command listed in the sections below.
Upgrade your current RamDisc software to revision 4.03 or greater (your support
contract allows an online license upgrade from release 3 to 4 using our website).
If a disk device file that is either mirrored to a RamDisc voume group or part of
a RamCluster changes in ioscan to another device file (due to changes to the I/O
of the system), contact RamDisc technical support before performing the following.
Section 1: Working with RamOnly volume groups (no mirroring and no ServiceGuard)
Section 2: Working with RamDisc mirrored volume groups (without ServiceGuard)
Section 3: Working with RamCluster mirrored volume groups (ServiceGuard packages)
Section 1: Working with RamOnly volume groups (no mirroring and no ServiceGuard)
Using RamDisc software revision 4.03 or greater only requires a scheduled reboot
of each configured system to restore the RamOnly volume groups. While activated,
the volume group(s) will remain online and useable until the next system shutdown.
Section 2: Working with RamDisc mirrored volume groups (without ServiceGuard)
Make a backup copy of /etc/rc.config.d/ramvol and place it in /tmp directory. The
backup copy must not reside in the /etc/rc.config.d directory. Open the ramvol
file (in /etc/rc.config.d dir) for edit. Look at the PVCPRI_DISK variables. There
are 9 indexed variables of this type. Note the index numbers of the PVCPRI_DISK
variables that contain disk device files. The index number (a number between the
left and right bracket) will match the last character of the RamDisc volume group
name(s) that are mirrored (/dev/vr0x). You will also notice 9 indexed variables
called VGROUP_STAT. For any PVCPRI_DISK variable that has device files defined,
change the VGROUP_STAT variable within the same index number from the word Enable
to Import (Note the uppercase letter 'I' as this word is case sensitive). Reboot
the system after saving changes to the file and the volume group will be restored.
Section 3: Working with RamCluster mirrored volume groups (ServiceGuard packages)
Make sure that any packages with a RamCluster configured are halted and will not
auto start when the cluster is started. Besides changing the word Standby to the
phrase RCport (Note the uppercase letter 'R' and 'C'), follow the instructions in
Section 2 on each system the vgscan command was executed, then reboot each system
so the cluster is formed but not running any packages containing RamClusters. Log
in to each system and change to the /usr/local/etc/ramdisc/sysadmin directory. In
this directory you will see files that have a ramcluster_ prefix. For each volume
group configured as a RamCluster, run ./ramcluster_postvgscan /dev/vr0x (letter x
matches the last character of the volume group name and the index number(s) noted
in the ramvol file). If you used vgscan on both systems in the cluster, you will
need to run the ramcluster_postvgscan script on the other system as well with the
warning that it is very important to wait until the script completes on the initial
system first. (Do not execute more than once per volume group or simultaneously.)
After the ramcluster_postvgscan script has been run for each RamCluster volume
group (as needed on the other system as well), to check functionality, execute
./ramcluster_run (only on 1 system) and check the mounted filesystems. When you
are satisfied, execute ./ramcluster_halt and the RamCluster lvols will be offline
and the volume group(s) deactivated. Perform the same steps with ramcluster_run
and ramcluster_halt on the partner system to insure it works as well. You can now
start your packages and configure them for auto run if you desire. An additional
test would be to shutdown and reboot both systems if you have spare time to do so.
Please note that the RamDisc automated LVM recovery from a vgscan command as documented above
can only be performed if your current RamDisc software revision is 4.03 or greater.
