Compaq StorageWorks HSZ80 Configuration And Cli Reference Manual page 302

5–116 CLI Commands
Specify NOPOLICY to prevent the controller from automatically replacing a failed
disk device. The mirrorset operates in a reduced state until a POLICY=BEST_FIT or
POLICY=BEST_PERFORMANCE is selected, or a member is manually placed in
the mirrorset.
READ_SOURCE=disk-name
READ_SOURCE=LEAST_BUSY (Default)
READ_SOURCE=ROUND_ROBIN
Selects the mirrorset member used by the controller to satisfy a read request. A
member with REMOTE set may be selected.
Specify the READ_SOURCE=disk-name of a specific member to which you want the
controller to direct all read requests. If the member fails out of the mirrorset, the
controller selects the first normal member it finds to satisfy its read requests.
Specify READ_SOURCE=LEAST_BUSY to direct read requests to the mirrorset
member with the least amount of work in its queue. If multiple members have equally
short queues, the controller queries these members for each read request as it would
when READ_SOURCE=ROUND_ROBIN is specified. If no normal local disk exists,
then the controller will query the remote disks.
Specify READ_SOURCE=ROUND_ROBIN to sequentially direct read requests to
each mirrorset member. The controller equally queries all normal members for each
read request. If no normal local disk exists, then the controller will query the remote
disks.
Examples
This example shows how to change the replacement policy of mirrorset MIRR1 to
BEST_FIT:
SET MIRR1 POLICY=BEST_FIT