Veritas Volume Manager 5.0.1 Troubleshooting Guide, HP-UX 11i v3, First Edition, November 2009

■ Case 1: Some arrays such as EMC and HDS provide mirroring in hardware.
When a LUN pair is split, depending on how the process is performed, this can
result in two disks that have the same disk identifier and UDID value. See
"Handling Disks with Duplicated Identifiers" in the "Creating and Administering
Disk Groups" chapter of the Veritas Volume Manager Administrator’s Guide
for full details of how to deal with this condition.
■ Case 2: If disks have been duplicated by using the dd command or any similar
copying utility, you can use the following command to update the UDID for
one or more disks:
# vxdisk [-f] updateudid disk1 ...
This command uses the current value of the UDID that is stored in the Device
Discovery Layer (DDL) database to correct the value in the private region. The
-f option must be specified if VxVM has not set the udid_mismatch flag on a
disk.
For example, the following command updates the UDIDs for the disks c2t66d0
and c2t67d0:
# vxdisk updateudid c2t66d0 c2t67d0
■ Case 3: If DMP has been disabled to an array that has multiple paths, then each
path to the array is claimed as a unique disk.
If DMP is suppressed, VxVM does not know which path to select as the true
path. You must choose which path to use. Decide which path to exclude, and
then select item 1 (suppress all paths through a controller from VxVM’s
view) or item 2 (suppress a path from VxVM’s view) from vxdiskadm option
17 (Prevent multipathing/Suppress devices from VxVM’s view).
115Error messages
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