Specifications

4–40 Planning Storagesets
■ COPY=FAST allocates more resources to reconstructing the replacement disk
drive, which may reduce the subsystem’s overall performance during the
reconstruction task.
Read Source
Specify the read source to determine how the controller reads data from the members
of a mirrorset:
■ READ_SOURCE=LEAST_BUSY (default) forces the controller to read data
from the “normal” or operational member that has the least-busy work queue. If
multiple disks have equally short queues, the controller queries normal local
disks 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 any remote disks if available.
■ READ_SOURCE=ROUND_ROBIN forces the controller to read data
sequentially from all “normal” or operational members in a mirrorset. For
example, in a four-member mirrorset (A, B, C, and D), the controller reads from
A, then B, then C, then D, then A, then B, and so forth. No preference is given to
any member. If no normal local disk exists, then the controller will query any
remote disks if available.
■ READ_SOURCE=DISKnnnnn forces the controller to always read data from a
particular “normal” or operational member. If the specified member fails, the
controller reads from the least busy member.