fence_scsi(8)fence_scsi(8)NAMEfence_scsi - I/O fencing agent for SCSI persistent reservations
DESCRIPTIONfence_scsi is an I/O fencing agent that uses SCSI-3 persistent reserva‐
tions 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, reg‐
istrants 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. In the cluster
environment unfence action should be configured also.
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 multi‐
path devices or raw devices. If using a device-mapper multipath device,
the fence_scsi agent will find the underlying devices (paths) and cre‐
ated registrations for each path.
Fencing action. This value can be "on", "off", "status", or
"metadata". The "on", "off", and "status" 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 "metadata" action will display
the XML metadata. The default action if "off".
List of devices to use for current operation. Devices can be
comma-separated list of raw device (eg. /dev/sdc) or device-map‐
per multipath devices (eg. /dev/dm-3). Each device must support
SCSI-3 persistent reservations.
Log output to file.
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 speci‐
fies the key to be removed from the device(s).
Wait X seconds before fencing is started (Default Value: 0)
-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
-v Verbose output.
-V Print out a version message, then exit.
agent = "param"
This option is used by fence_node(8) and is ignored by
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.
delay = "param"
Same as -H option.
aptpl = "1"
Enable the APTPL flag. Default is 0 (disable).
SEE ALSOfence(8), fence_node(8), sg_persist(8), vgs(8), cman_tool(8), cman(5)fence_scsi(8)