SCF Reference Manual for the Storage Subsystem (G06.27+, H06.04+)

Storage Subsystem Commands
SCF Reference Manual for the Storage Subsystem—529937-008
14-28
Disk Attribute Descriptions
During the process of reviving a mirrored disk volume, DP2 must perform the time-
consuming task of copying data from the STARTED half of the disk volume to the
half that is in the REVIVE substate.
The REVIVEPRIORITY attribute specification can lessen the impact of this task on
system resources by giving the task a lower priority. For example, if
REVIVEPRIORITY is 50, the revive process defers to new requests with a priority
above 50. Specifying a lower priority value ensures that the revive operation does
not impact higher priority workloads, but it does lengthen the time that the revive
operation takes.
You can adjust the REVIVEPRIORITY value during the revive operation to speed
or slow the revive progress.
The minimum value for REVIVEPRIORITY is 0, and the maximum value is 199.
The default value is 0, which causes DP2 to use its internal default of 50
REVIVERATE number
determines the amount of data revived between preemption checks. The higher
the rate, the more the impact on higher priority workloads; the lower the rate, the
less the impact on higher priority workloads. At the same time, the higher the rate,
the faster the revive operation, and the lower the rate, the slower the revive
operation.
The minimum value is 0, and the maximum value is 100. The default value is 0,
which causes DP2 to use its internal default of 50.
This table shows the effects of specifying high and low values in the number field
of the REVIVEPRIORITY and REVIVERATE attributes when you specify these
attributes in combination. For Rate, Low equals the range 0 through 50, and High
equals the range 51 through 100.
DP2's internal default REVIVEPRIORITY of 50 (low) and REVIVERATE of 100
(high) is typically acceptable for most environments. If there is any impact to
concurrent activity, lower the REVIVERATE until the impact is reduced to an
acceptable level.
Priority Rate Effect
Low Low This combination ensures the lowest possible impact to
online activity. If there is no online activity, the revive
progress is slightly throttled by a low rate.
Low High This combination ensures that the revive makes
progress, but it has limited impact to online activity. If
there is no online activity, the revive progress will be as
fast as possible.
High High This combination ensures that the revive makes
progress, but it has limited impact to online activity. If
there is no online activity, the revive progress will be as
fast as possible.