HP Array Controller HSG V8.7 Software - Manual (Page 121)

Creating Storagesets 3–43
Read Source
Specify the read source to determine how the controller reads data from
the members of a mirrorset:
n 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.
n 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.
n 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.