fence_mpath is an I/O fencing agent that uses SCSI-3 persistent reservations to control access multipath devices. Underlying devices must support SCSI-3 persistent reservations (SPC-3 or greater) as well as the "preempt-and-abort" subcommand. The fence_mpath agent works by having a unique key for each node that has to be set in /etc/multipath.conf. Once registered, a single node will become the reservation holder by creating a "write exclusive, registrants only" reservation on the device(s). The result is that only registered nodes may write to the device(s). When a node failure occurs, the fence_mpath agent will remove the key belonging to the failed node from the device(s). The failed node will no longer be able to write to the device(s). A manual reboot is required. When used as a watchdog device you can define e.g. retry=1, retry-sleep=2 and verbose=yes parameters in /etc/sysconfig/stonith if you have issues with it failing. https://www.sourceware.org/dm/ Fencing action List of devices to use for current operation. Devices can be comma-separated list of device-mapper multipath devices (eg. /dev/mapper/3600508b400105df70000e00000ac0000 or /dev/mapper/mpath1). Each device must support SCSI-3 persistent reservations. Replaced by port/-n/--plug Key to use for the current operation. This key should be unique to a node and have to be written in /etc/multipath.conf. For the "on" action, the key specifies the key use to register the local node. For the "off" action, this key specifies the key to be removed from the device(s). Key to use for the current operation. This key should be unique to a node and have to be written in /etc/multipath.conf. For the "on" action, the key specifies the key use to register the local node. For the "off" action, this key specifies the key to be removed from the device(s). Error log suppression. Error log suppression. Disable logging to stderr. Does not affect --verbose or --debug-file or logging to syslog. Verbose mode. Multiple -v flags can be stacked on the command line (e.g., -vvv) to increase verbosity. Level of debugging detail in output. Defaults to the number of --verbose flags specified on the command line, or to 1 if verbose=1 in a stonith device configuration (i.e., on stdin). Write debug information to given file Write debug information to given file Display version information and exit Display help and exit Separator for plug parameter when specifying more than 1 plug Wait X seconds before fencing is started Disable timeout (true/false) (default: true when run from Pacemaker 2.0+) Wait X seconds for cmd prompt after login Path to mpathpersist binary Test X seconds for status change after ON/OFF Wait X seconds after issuing ON/OFF Wait X seconds for cmd prompt after issuing command Sleep X seconds between status calls during a STONITH action Path to directory where fence agent can store information Count of attempts to retry power on Use sudo (without password) when calling 3rd party software Use sudo (without password) when calling 3rd party software Path to sudo binary