Setting the SCSI command timeout

Red Hat Enterprise Linux 8.6 LPAR mode z/VM guest

You can change the timeout if the default is not suitable for your storage system.

Before you begin

The FCP device must be online.

About this task

There is a timeout for SCSI commands. If the timeout expires before a SCSI command completes, error recovery starts. The default timeout is 30 seconds.

To find out the current timeout, read the timeout attribute of the SCSI device:

# cat /sys/bus/scsi/devices/<scsi_host_no>:0:<scsi_id>:<scsi_lun>/timeout

where:

<scsi_host_no>: is the SCSI host number that corresponds to the FCP device.
<scsi_id>: is the SCSI ID of the target port.
<scsi_lun>: is the LUN of the SCSI device.

The attribute value specifies the timeout in seconds.

Procedure

To set a different timeout, enter a command of this form:

# echo <timeout> > /sys/bus/scsi/devices/<scsi_host_no>:0:<scsi_id>:<scsi_lun>/timeout

where <timeout> is the new timeout in seconds.

Example

In the following example, the timeout of a SCSI device 1:0:18:1086537744 is first read and then set to 45 seconds:

# cat /sys/bus/scsi/devices/1:0:18:1086537744/timeout
30
# echo 45 > /sys/bus/scsi/devices/1:0:18:1086537744/timeout