Cx set rebuildmode=<adaptive|lowlatency, Cx set rebuildrate=<1, Set rebuildmode=<adaptive|lowlatency – Avago Technologies 3ware SAS 9750-4i User Manual
Page 78
Chapter 2. CLI Syntax Reference
70
3ware SATA+SAS RAID Controller Card CLI Guide, Version 10.0
/c
x
set rebuildmode=<adaptive|lowlatency>
This command is only supported on 9750, 9690SA, and 9650SE controllers.
This command sets the rebuild mode. The rebuild mode has two settings:
Adaptive and Low Latency.
Rebuild mode works in conjunction with the rebuild task rate (see “/cx set
rebuildrate=<1...5>” on page 70).
The Adaptive setting is the default rebuild mode. It allows the firmware to
adjust the interaction of rebuild tasks with host I/Os to maximize the speed of
both host I/O and rebuild tasks. When a rebuild background task is active, if
the task rate is set to a fast rebuild rate (i.e., low I/O rate), the system latency
increases and performance may be negatively affected, especially for
applications such as video server applications and audio applications. The
Low Latency setting will minimize the latency (delay) in reading data from
the RAID unit by slowing down the rebuild task, which allows host Reads to
complete, thus improving performance.
For a more complete discussion of background task modes, see “Working
with the Background Task Mode” in the 3ware SATA+SAS RAID Controller
Card Software User Guide, Version 10.0.
Example:
//localhost> /c1 set rebuildmode=lowlatency
Setting Rebuild background task mode of /c1 to [lowlatency] ... Done.
Related commands:
/cx set rebuildrate=<1...5>
This command sets the rebuild task rate of the specified controller. The
rebuild task rate sets the rebuild execution priority relative to I/O operations.
This task rate is of the range [1..5], where 5 denotes the setting of fastest
background task and slowest I/O, as follows:
5 = fastest rebuild; slowest I/O
4 = faster rebuild; slower I/O
3 = balanced between rebuild and I/O
Important:
Setting rebuildmode to 'low latency' and rebuildrate to '5' is not
recommended when I/O is active, because in that case, the rebuild as a
background task may never complete. Thus, this setting should be used with care.