HP Serviceguard A.11.20- Managing Serviceguard Twentieth Edition, August 2011

IMPORTANT: If you need to replace a LUN under the HP-UX 11i v3 agile addressing scheme,
also used by cDSFs (see “About Device File Names (Device Special Files)” (page 80) and “About
Cluster-wide Device Special Files (cDSFs)” (page 104), and you use the same DSF, you may need
to use the io_redirect_dsf(1M) command to reassign the existing DSF to the new device,
depending on whether the operation changes the WWID of the LUN; see the section on
io_redirect_dsf in the white paper The Next Generation Mass Storage Stack at http://
www.hp.com/go/hpux-core-docs.
If you are not able to use the existing DSF for the new device, or you decide not to, you must
change the name of the DSF in the cluster configuration file and re-apply the configuration; see
“Updating the Cluster Lock LUN Configuration Online” (page 295). Do this after running
vgcfgrestore as described below.
CAUTION: Before you start, make sure that all nodes have logged a message such as the following
in syslog:
WARNING: Cluster lock LUN /dev/dsk/c0t1d1 is corrupt: bad label. Until
this situation is corrected, a single failure could cause all nodes in
the cluster to crash.
Once all nodes have logged this message, use a command such as the following to specify the
new cluster lock LUN:
cmdisklock reset /dev/dsk/c0t1d1
cmdisklock checks that the specified device is not in use by LVM, VxVM, ASM, or the file system,
and will fail if the device has a label marking it as in use by any of those subsystems. cmdisklock
-f overrides this check.
CAUTION: You are responsible for determining that the device is not being used by any subsystem
on any node connected to the device before using cmdisklock -f. If you use cmdisklock
-f without taking this precaution, you could lose data.
NOTE: cmdisklock is needed only when you are repairing or replacing a lock LUN or lock
disk; see the cmdisklock (1m) manpage for more information.
Serviceguard checks the lock LUN every 75 seconds. After using the cmdisklock command,
review the syslog file of an active cluster node for not more than 75 seconds. By this time you
should see a message showing that the lock LUN is healthy again.
Online Hardware Maintenance with In-line SCSI Terminator
In some shared SCSI bus configurations, online SCSI disk controller hardware repairs can be made
if HP in-line terminator (ILT) cables are used. In-line terminator cables are supported with most
SCSI-2 Fast-Wide configurations.
In-line terminator cables are supported with Ultra2 SCSI host bus adapters only when used with
the SC10 disk enclosure. This is because the SC10 operates at slower SCSI bus speeds, which
are safe for the use of ILT cables. In-line terminator cables are not supported for use in any Ultra160
or Ultra3 SCSI configuration, since the higher SCSI bus speeds can cause silent data corruption
when the ILT cables are used.
Replacing I/O Cards
Replacing SCSI Host Bus Adapters
After a SCSI Host Bus Adapter (HBA) card failure, you can replace the card using the following
steps.
326 Troubleshooting Your Cluster