HP StorageWorks HSG60 and HSG80 Array Controller and Array Controller Software Command Line Interface Reference Guide (EK-G80CL-RA. C01, March 2005)

CLI Command Descriptions
158 HP StorageWorks HSG60 and HSG80 Array Controller and Array Controller Software
Command Line Interface Reference Guide
Removes member disk drives from mirrorsets and decreases the nominal number
of members in the mirrorsets.
This command does not put reduced members into the failedset (unlike the
REMOVE=disk-name switch that is used with the SET mirrorset-name
command). If you are using the REDUCE command to take a snapshot of a striped
mirrorset, you must reduce all mirrorsets with one command. The CLONE utility
does this automatically.
The nominal number of members in a mirrorset is determined by the number of
members assigned to the mirrorset with the
MEMBERSHIP=number-of-members switch that is used with SET
mirrorset-name command or the mirrorset-name and disk-name1
[disk-nameN] parameters that are used with the ADD MIRRORSETS
command—in other words, the number of disks that the mirrorset originally
contained before it was reduced. The actual number of members contained in the
mirrorset can be less than the nominal number of members if:
■ A disk drive is not added back to the mirrorset.
■ A member remains removed from the mirrorset.
■ The mirrorset replacement policy NOPOLICY switch is specified with the
SET mirrorset-name command.
■ No spare disks exist.
The actual number of members in the mirrorset can never be greater than the
nominal number of members. The disks to be removed do not need to be members
of the same mirrorset. However, the disks must all be part of the same unit (for
example, the same striped mirrorset). If a disk is reduced from a mirrorset, the
controller:
■ Flushes all unit data from writeback data cache.
■ Pauses I/O to the unit.
■ Removes the specified disks.
■ Decreases the nominal number of members of the mirrorsets by the number of
disks removed from the mirrorsets.
■ Re-establishes I/O to the unit.
REDUCE