User`s manual

6-43
Storage Manager
Background Task Priority
You can run rebuild and verification operations without taking an array
offline. These functions are performed as background tasks on the
SmartRAID V controller and are transparent to the host operating system.
However, the controller interleaves I/O from the operating system with I/O
from the background task and this can affect system performance. The
relative priority given to I/O from the operating system and the
background task can be controlled by selecting Options–Background
Task Priority.
The Task Priority section of the dialog assigns the background task
priority for all DPT controllers in the host computer. Set the Priority by
using the arrow buttons to move the indicator . The indicator moves
between Background and Foreground in ten increments.
If the indicator is closer to Background, background tasks are processed
only when there is no disk I/O from the host for a period of at least 250
milliseconds. As the indicator is moved toward Foreground, more of the
controller resources are allocated to background tasks. All of the
resources are allocated to background tasks during periods when there is
no disk I/O from the host system.