If a multipath device is configured with
features "1 queue_if_no_path", then any process that issues I/O will hang until one or more paths are restored. To avoid this, set the
N parameter in the
/etc/multipath.conf file (where
N is the number of times the system should retry a path).
If you need to use the
features "1 queue_if_no_path" option and you experience the issue noted here, use the
dmsetup command to edit the policy at runtime for a particular LUN (that is, for which all the paths are unavailable). For example, if you want to change the policy on the multipath device
"fail_if_no_path", execute the following command.
dmsetup message mpathc 0 "fail_if_no_path"
Note that you must specify the
n alias rather than the path.