Veritas Storage Foundation 5.0.1 Cluster File System Administrator's Guide Extracts for the HP Serviceguard Storage Management Suite on HP-UX 11i v3

Limitations of Shared Disk Groups
NOTE: The boot disk group (usually aliased as bootdg) cannot be made cluster-shareable. It
must be private.
Only raw device access can be performed via the cluster functionality of VxVM. It does not
support shared access to file systems in shared volumes unless the appropriate software, such
as the HP Serviceguard Storage Management Suite, is installed and configured.
The cluster functionality of VxVM does not support RAID-5 volumes, or task monitoring for
cluster-shareable disk groups. These features can, however, be used in private disk groups that
are attached to specific nodes of a cluster.
If you have RAID-5 volumes in a private disk group that you wish to make shareable, you must
first relayout the volumes as a supported volume type such as stripe-mirror or mirror-stripe.
Online relayout is supported provided that it does not involve RAID-5 volumes.
If a shared disk group contains unsupported objects, deport it and then re-import the disk group
as private on one of the cluster nodes. Reorganize the volumes into layouts that are supported
for shared disk groups, and then deport and re-import the disk group as shared.
Recovery in a CVM Environment
In a Cluster Volume Manager environment, when one set of mirrored disks fails and gets replaced,
vxreattach fails to recognize the replaced disk. The exact error message is: Device path
not valid When reattaching failed disks to a Cluster Volume Manager (CVM) cluster, the
correct procedure requires running the vxdctl enable command on all nodes and running
the vxreattach command with the -r option on the master node. This initiates a vxrecover
command to recover all volumes.
Follow these steps to reattach failed disks to a CVM cluster:
1. Confirm that paths and devices are ready for I/O, using the dd command:
# dd if=/dev/rdsk/c6t2d1 of=/dev/null bs=1k count=1010+0 records
in10+0 records out#
2. Execute the vxdctl enable command on all nodes in the cluster
3. On the master node, reattach and recover all volumes with the vxreattach command,
using the -r option:
# vxreattach -r <device>
All devices should now be recognized by all nodes in the cluster.
NOTE: Halting the cluster, rebooting all the cluster nodes, and restarting the cluster will also
result in proper device recognition.
34 Cluster Volume Manager Administration