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Avago Technologies 3ware SAS 9750-16i4e User Manual

Page 173

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Background Tasks

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161

Figure 80. Low Latency Mode with warning when Rate=1

Table 13 provides an overview of the impact of selecting different Task Rate
and Task Mode settings.

Note:

The Background Task Rate and Background Task Mode settings are only

relevant when there is host I/O activity. When there is no host activity, background
tasks (rebuild/migrate, initialization, and verify) always run at the maximum.

Table 13: Selecting Appropriate Background Task Rate and Mode

Your priority

Rebuild
Task Rate

Task
Mode

Comments

Fastest rebuild time

5

Adaptive

Potential for higher latency on
host I/Os

Balanced host I/O
and rebuild tasks

3

Adaptive

Default setting

Minimized host I/O
latency

2

Low
Latency

Background tasks will complete,
but will be slow when there are
host I/Os

Minimum host I/O
latency

1

Low
Latency

Background tasks may never
finish when there are continuous
host I/Os. For example, a rebuild
may never complete.