LSI 9690SA-8E-KIT Guide d'installation télécharger pdf (Page 75)

Controller Object Commands

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When a verify background task is active, if the task rate is set to a fast verify

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 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 10.2.

Example:

//localhost> /c1 set verifymode=lowlatency

Setting Verify background task mode of /c1 to [lowlatency] ... Done.

Related commands:

/cx show verifymode

/cx set verifyrate=<1..5>

/cx show verifyrate

/cx set verifyrate=<1..5>

The /cx set verifyrate command sets the verify task rate of the specified

controller. The verify task rate sets the verify 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 verify; slowest I/O

4 = faster verify; slower I/O

3 = balanced between verify and I/O

2 = faster I/O; slower verify

1 = fastest I/O; slowest verify

Example:

//localhost> /c1 set verifyrate=2

Setting Verify background task rate on /c1 to [2] (faster I/O)

... Done.

Important: Setting verifymode to low latency and verifyrate to 5 is not

recommended when I/O is active because, in that case, the verify as a background

task might never complete. Use this setting with care.

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LSI 9690SA-8E-KIT Guide d'installation Page 75