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 multipath 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)