4.6. iSCSI and DM Multipath overrides

The recovery_tmo sysfs option controls the timeout for a particular iSCSI device. The following options globally override recovery_tmo values:

The replacement_timeout configuration option globally overrides the recovery_tmo value for all iSCSI devices.
For all iSCSI devices that are managed by DM Multipath, the fast_io_fail_tmo option in DM Multipath globally overrides the recovery_tmo value. The fast_io_fail_tmo option in DM Multipath also overrides the fast_io_fail_tmo option in Fibre Channel devices.
The DM Multipath fast_io_fail_tmo option takes precedence over replacement_timeout. Red Hat does not recommend using replacement_timeout to override recovery_tmo in devices managed by DM Multipath because DM Multipath always resets recovery_tmo when the multipathd service reloads.