Managing Serviceguard Nineteenth Edition, Reprinted June 2011

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 77).
If you are using cDSFs, the device file would be in the /dev/rdisk/ directory; for example
/dev/rdisk/disk1. See “About Cluster-wide Device Special Files (cDSFs)” (page 99).
If you need to replace a disk under the 11i v3 agile addressing scheme (also used by cDSFs),
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://www.hp.com/go/hpux-core-docs.
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 a Lock Disk
You can replace an unusable lock disk while the cluster is running. You can do this without any
cluster reconfiguration if you do not change the devicefile name (Device Special File, or DSF); or,
if you need to change the DSF, you can do the necessary reconfiguration while the cluster is
running.
Replacing Disks 311