Managing Serviceguard Eighteenth Edition, September 2010

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.
Normally disconnecting any portion of the SCSI bus will leave the SCSI bus in an
unterminated state, which will cause I/O errors for other nodes connected to that SCSI
bus, so the cluster would need to be halted before disconnecting any portion of the
SCSI bus. However, it is not necessary to bring the cluster down to do this if you are
using a SCSI configuration that allows disconnection of a portion of the SCSI bus
without losing termination.
SCSI bus configurations using SCSI in-line terminators or Y cables at each node, or
using a SCSI device which auto-terminates its ports when disconnected (such as the
MSA30 MI), can allow online repair.
406 Troubleshooting Your Cluster