Timeouts for autoquiesce

7.1 LPAR mode z/VM guest KVM guest

Use the aq_timeouts sysfs attribute to specify after how many timeouts to trigger an autoquiesce event.

About this task

The default value is 32768 which is the maximum number of retries for the DASD device driver DASD_RETRIES_MAX. This means that the timeout is never triggered. The default value for DASD retries is 255.

Set the value to below 255 to trigger the timeout autoquiesce event before an IO error is generated.

If you change the DASD retries value to more than 255, then an aq_timeouts value up to that value triggers an autoquiesce event after that number of timeouts.

Examples

To trigger an autoquiesce event before an IO error is generated, write for example 250 to the aq_timeouts attribute:
```
$ echo 250 > /sys/bus/ccw/0.0.1234/aq_timeouts 
```
where 0.0.1234 is the device-bus ID of the DASD.
To trigger an autoquiesce event after 100 timeouts, issue:
```
$ echo 100 > /sys/bus/ccw/0.0.1234/aq_timeouts
```