rpc.lockd, lockd - Network lock daemon
/usr/sbin/rpc.lockd [-b hostname] [-c] [-d debug] [-g graceperiod] [-h
hashsize] [-s] [-t timeout]
The default behavior will create and bind a socket for each protocol
per interface on the system. When the -b switch is specified, one
socket per protocol will be created and bind to the passed IP address.
Available only on TruCluster Server systems. This option starts the
clusterwide lock daemon, which helps provide highly available NFS ser‐
vice. Do not use -c directly. Highly available NFS service is config‐
ured by default and typically does not require intervention. If you do
need to start the clusterwide lock daemon, use the CAA command,
For more information, see the TruCluster Server Administration
manual. Internal Use Only. Use this option only under the
direction of technical support personnel. Causes the rpc.lockd
daemon to use the variable graceperiod (in seconds) as the grace
period duration instead of the default value of 15 seconds. On
TruCluster Server systems the default value is 30 seconds.
Internal Use Only. Causes the rpc.lockd daemon to use the vari‐
able timeout (in seconds) as the interval instead of the default
value of 5 seconds to retransmit a lock request to the remote
The rpc.lockd daemon processes lock requests that are either sent
locally by the kernel or remotely by another lock daemon. The NFS lock‐
ing service makes this advisory locking support possible by using the
fcntl system call and the lockf subroutine. The rpc.lockd daemon for‐
wards lock requests for remote data to the server site's lock daemon.
The rpc.lockd daemon then requests the status monitor daemon,
rpc.statd, for monitor service. The reply to the lock request is not
sent to the kernel until the status daemon and the server site's lock
daemon have replied.
If either the status monitor or server site's lock daemon is unavail‐
able, the reply to a lock request for remote data is delayed until all
daemons become available.
When a server recovers, it waits for a grace period for all client site
lock daemons to submit reclaim requests. Client site lock daemons are
notified by rpc.statd of the server recovery and promptly resubmit pre‐
viously granted lock requests. If a client site's lock daemon fails to
secure previously granted locks at the server site, it sends the signal
SIGLOST to all the processes that were previously holding locks and
cannot reclaim them.
Functions: fcntl(2), signal(2), lockf(3)rpc.lockd(8)