fence_scsi(8)						      System Manager's Manual						     fence_scsi(8)

NAME

       fence_scsi - I/O fencing agent for SCSI persistent reservations

SYNOPSIS

       fence_scsi [OPTION]...

DESCRIPTION

       fence_scsi is an I/O fencing agent that uses SCSI-3 persistent reservations to control access to shared storage devices. These devices must
       support SCSI-3 persistent reservations (SPC-3 or greater) as well as the "preempt-and-abort" subcommand.

       The fence_scsi agent works by having each node in the cluster register a unique key with the SCSI devive(s). 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_scsi 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.

       Keys  are  either  be specified manually (see -k option) or generated automatically (see -n option). Automatic key generation requires that
       cman be running. Keys will then be generated using the cluster ID and node ID such that each node has a unique key that can  be	determined
       by any other node in the cluster.

       Devices can either be specified manually (see -d option) or discovered automatically. Multiple devices can be specified manually by using a
       comma-separated list. If no devices are specified, the fence_scsi agent will attempt to discover devices by looking for cluster volumes and
       extracting  the	underlying  devices.  Devices  may  be	device-mapper multipath devices or raw devices. If using a device-mapper multipath
       device, the fence_scsi agent will find the underlying devices (paths) and created registrations for each path.

OPTIONS

       -o action
	      Fencing action. This value can be "on", "off", or "status". All actions require either a key (see -k option) or node  name  (see	-n
	      option).	For  "on", the agent will attempt to register with the device(s) and create a reservation if none exists. The "off" action
	      will attempt to remove a node's key from the device(s). The "status" action will report whether or not a	node's	key  is  currently
	      register with one or more of the devices. The default action if "off".

       -d devices
	      List of devices to use for current operation. Devices can be comma-separated list of raw device (eg. /dev/sdc) or device-mapper mul-
	      tipath devices (eg. /dev/dm-3). Each device must support SCSI-3 persistent reservations.

       -f logfile
	      Log output to file.

       -n nodename
	      Name of the node to be fenced. The node name is used to generate the key value used for the current operation. This option  will	be
	      ignored when used with the -k option.

       -k key Key  to  use  for  the current operation. This key should be unique to a node. 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).

       -a     Use the APTPL flag for registrations. This option is only used for the "on" action.

       -h     Print out a help message describing available options, then exit.

       -v     Verbose output.

       -V     Print out a version message, then exit.

STDIN PARAMETERS

       agent = "param"
	      This option is used by fence_node(8) and is ignored by fence_scsi.

       nodename = "param"
	      Same as -n option.

       action = "param"
	      Same as -o option.

       devices = "param"
	      Same as -d option.

       logfile = "param"
	      Same as -f option

       key = "param"
	      Same as -k option.

       aptpl = "1"
	      Enable the APTPL flag. Default is 0 (disable).

SEE ALSO

       fence(8), fence_node(8), sg_persist(8), vgs(8), cman_tool(8), cman(5)

																     fence_scsi(8)