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5.5. Issues with queue_if_no_path
If features "1 queue_if_no_path" is specified in the /etc/multipath.conf file, then any process that uses I/O will hang until one or more paths are restored. To avoid this, set the no_path_retry N parameter in the / etc/multipath.conf.
When you set the no_path_retry parameter, remove the features "1 queue_if_no_path" option from the /etc/multipath.conf file as well. If, however, you are using a multipathed device for which the features "1 queue_if_no_path" option is set as a compiled in default, as it is for many SAN devices, you must add features "0" to override this default. You can do this by copying the existing devices section, and just that section (not the entire file), from /usr/share/doc/multipath-tools/examples/ multipath.conf.annotated.gz into /etc/multipath.conf and editing to suit your needs.
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 mpathc from "queue_if_no_path" to "fail_if_no_path", execute the following command.
# dmsetup message mpathc 0 "fail_if_no_path"
You must specify the mpathN alias rather than the path