Managing Serviceguard Sixteenth Edition, March 2009

Replacing a Faulty Mechanism in an HA Enclosure
If you are using software mirroring with Mirrordisk/UX and the mirrored disks are
mounted in a high availability disk enclosure, you can use the following steps to hot
plug a disk mechanism:
1. Identify the physical volume name of the failed disk and the name of the volume
group in which it was configured. In the following example, the volume group
name is shown as /dev/vg_sg01 and the physical volume name is shown as
/dev/dsk/c2t3d0. Substitute the volume group and physical volume names
that are correct for your system.
NOTE: This example assumes you are using legacy DSF naming. Under agile
addressing, the physical volume would have a name such as /dev/disk/disk1.
See “About Device File Names (Device Special Files)” (page 107).
If you need to replace a disk under the 11i v3 agile addressing scheme, you may
be able to reduce downtime by using the io_redirect_dsf(1M) command to
reassign the existing DSF to the new device. See the section Replacing a Bad Disk
in the Logical Volume Management volume of the HP-UX System Administrator’s
Guide, posted at http://docs.hp.com.
2. Identify the names of any logical volumes that have extents defined on the failed
physical volume.
3. On the node on which the volume group is currently activated, use the following
command for each logical volume that has extents on the failed physical volume:
lvreduce -m 0 /dev/vg_sg01/lvolname /dev/dsk/c2t3d0
4. At this point, remove the failed disk and insert a new one. The new disk will have
the same HP-UX device name as the old one.
5. On the node from which you issued the lvreduce command, issue the following
command to restore the volume group configuration data to the newly inserted
disk:
vgcfgrestore -n /dev/vg_sg01 /dev/dsk/c2t3d0
6. Issue the following command to extend the logical volume to the newly inserted
disk:
lvextend -m 1 /dev/vg_sg01 /dev/dsk/c2t3d0
7. Finally, use the lvsync command for each logical volume that has extents on the failed
physical volume. This synchronizes the extents of the new disk with the extents of
the other mirror.
lvsync /dev/vg_sg01/lvolname
Replacing Disks 365