HP StorageWorks HSG60 and HSG80 Array Controller and Array Controller Software Troubleshooting Guide (EK-G80TS-SA. C01, March 2005)

Alternative Controller Operations
271HSG60 and HSG80 Array Controller and Array Controller Software Troubleshooting Guide
■ Any device in error recovery, where the error recovery against the same
device results in two SCSI BUS resets within a 2 minute interval, fails with
the following conditions:
■ Normalized and redundant containers are reduced.
■ Normalizing and redundant containers are reduced only if the device that
caused the SCSI bus reset is the device that is in the normalizing target.
■ Non-redundant containers transition the unit to an Inoperative state. If the
host retries a command, a check condition and SK=2 (not ready)
with ASC/Q of 04_00 is reported. The host might retry the I/O until it
suspends its retry attempts.
Caution: If a controller fails out one member of a host-redundant unit leaving
only one remaining member, it is essential that you do one of the following:
■ Promptly repair the failed unit so that it can be placed back into service.
■ Issue the SET <unit> NOHOST_REDUNDANT CLI command on the
operational host-mirrored unit. If the unit failure exists on the subsystem,
and there is no redundancy (from the host perspective or LSM level), then,
for best availability to data, you must issue the SET <unit>
NOHOST_REDUNDANT CLI command on the operational unit to cause the
unit to enter into Failover mode. Otherwise, the controller (not knowing
that the other host-mirrored redundant mirror failed), performs a quick
failure to the host, rendering a once redundant volume, inoperative.