Installation guide

Chapter 2. CLI Syntax Reference
64 3ware SATA+SAS RAID Controller Card CLI Guide, Version 10.2
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 can be negatively affected, especially for
applications such as video server applications and audio applications. The
Low Latency setting minimizes the latency (delay) in reading data from the
RAID unit by slowing 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 10.2.
Example:
//localhost> /c1 set rebuildmode=lowlatency
Setting Rebuild background task mode of /c1 to [lowlatency] ... Done.
Related commands:
/cx show rebuildmode
/cx set rebuildrate=<1..5>
/cx show rebuildrate
/cx set rebuildrate=<1..5>
The /cx set rebuildrate 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 in the range of [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
2 = faster I/O; slower rebuild
1 = fastest I/O; slowest rebuild
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 might never complete. Use this setting with care.