rpc.lockd, lockd - Network lock daemon
/usr/sbin/rpc.lockd [ -t timeout ] [ -g graceperiod ]
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. 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.
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 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 previously 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.
Commands: fcntl(2), lockf(3), rpc.statd(8), signal(2) delim off