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.
-c 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 person-
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
-s Internal Use Only.
Causes the rpc.lockd daemon to use the variable timeout (in seconds) as
the interval instead of the default value of 5 seconds to retransmit a
lock request to the remote server.
The rpc.lockd daemon processes lock requests that are either sent locally
by the kernel or remotely by another lock daemon. The NFS locking service
makes this advisory locking support possible by using the fcntl system call
and the lockf subroutine. The rpc.lockd daemon forwards 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 unavailable,
the reply to a lock request for remote data is delayed until all daemons
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 previ-
ously 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
Functions: fcntl(2), signal(2), lockf(3)