Using Serviceguard Extension for RAC, 8th Edition, March 2009

NOTE: If your LVM installation requires online replacement of disk mechanisms, the use of
disk arrays may be required, because software mirroring of JBODs with MirrorDisk/UX does
not permit hot swapping for disks that are activated in shared mode.
Replacing a Mechanism in an HA Enclosure Configured with Exclusive LVM
Non-Oracle data that is used by packages may be configured in volume groups that use exclusive
(one-node-at-a-time) activation. If you are using exclusive activation and 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 examples, the volume group name is shown
as/dev/vg_sg01 and the physical volume name is shown as/dev/c2t3d0. Substitute the
volume group and physical volume names that are correct for your system.
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 /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
Online Replacement of a Mechanism in an HA Enclosure Configured with Shared
LVM (SLVM)
If you are using software mirroring for shared concurrent activation of Oracle RAC data with
MirrorDisk/UX and the mirrored disks are mounted in a high availability disk enclosure use the
following LVM command options to change/replace disks via OLR (On Line Replacement):
NOTE: This procedure supports either LVM or SLVM VG and is “online” (activated), which
uses an “online disk replacement” mechanism. It is supported for SLVM, however the PV being
replaced must be detached from each node. For example, running pvchange -a N /dev/dsk/
from one node only detaches the disk from that node's perspective.
1. Detach the target PV by using one of the following commands on each node of the cluster:
# pvchange -a n [pv path]
Use the pvchange command -a n [pv path] to detach only one path or replace a disk
if the primary path disk path is not performing well and you want to disable the path. The
pvchange -a n command detaches the single specified PV Link (device path). (If the path
was the path in use LVM will switch to any alternate PV Link that is still available.)
OR
128 Maintenance and Troubleshooting