HP-UX HB v13.00 Ch-13 - LVM

HP-UX Handbook – Rev 13.00 Page 79 (of 110)
Chapter 13 LVM
October 29, 2013
/etc/lvmtab file unless the –f option is used. The –f option restricts the operation
to the specified volume group (overwrite existing volume group entries in
/etc/lvmtab). If the /etc/lvmtab is moved to a new location before running the
vgscan –B comand, full effect of the command is taken on all configured volume
groups and /etc/lvmtab file gets recreated.
Following the invocation of vgscan –B command, use vgchange to reactivate the
corresponding volume group. This reconfigures the volume group with the
DSFs(both legacy and persistent DSFs corresponding to each of the physical
volume) in the /etc/lvmtab file. Legacy DSFs can later be removed using
vgreduce, leaving behind corresponding persistent DSFs. This facilitates a
phased migration from legacy to agile naming model, while the volume group
continues to remain active.
Backup the /etc/lvmpvg file, if it exists. After the vgreduce operations, restore the
backed-up /etc/lvmpvg file and replace legacy DSFs listed under the volume
group being migrated with corresponding persistent DSFs.
3. There is a shell script in /usr/contrib/bin/vgdsf, that can perform the migration
while the volume group remains active. The vgdsf performs following tasks:
 Extend the volume group with corresponding persistent DSFs:
1. Identify the legacy DSFs configured in the volume group, using
vgdisplay –v. Ignore alternate links.
2. For each legacy DSF found, find its corresponding persistent DSF,
using ioscan –m command.
3. If a physical volume is configured with 8 paths, remove one using
vgreduce. This will make room for additional persistent DSF.
4. Extend the volume group to add the persistent DSF, keeping it in
some physical volume group configuration, if any (/etc/lvmpvg file
gets automatically updated).
 Reduce the volume group of all legacy DSFs :
1. Identify all legacy DSFs configured in the volume group, using
vgdisplay –v
2. For each of the legacy DSF that also has a corresponding
persistent DSF configured, reduce the legacy DSF from the volume
group. If the corresponding persistent DSF is not configured in the
volume group, a message is displayed on screen and the command
continues with other DSFs.
 Back up the resault configuration, using the vgcfgbackup command.
 Activate all confugred volume groups in the system and identify the ones
requiring a migration, using vgchange –a.