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HP-UX 11i Version 3: February 2007

Technical documentation

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lockd: rpc.lockd — network lock daemon


/usr/sbin/rpc.lockd [-g graceperiod] [-l listen_min_backlog] [-t timeout] [nthreads]


The lockd utility is part of the NFS lock manager, which supports record lock and share lock operations on NFS files. See fcntl(2) and lockf(2). lockd provides two functions:

  • It forwards fcntl(2) locking requests for NFS mounted file systems to the lockd on the NFS server.

  • It generates local file locking operations in response to requests forwarded from lockd running on NFS client machines.

State information kept by the lockd about these locking requests can be lost if lockd is killed or the operating system is rebooted. Some of this information can be recovered as follows. When a server recovers, it waits for a grace period for all NFS client-site lockd to submit reclaim requests. Client-site lockd is notified by the statd(1M) of the server recovery, and promptly resubmits previously granted lock requests. If a lockd fails to secure a previously granted lock at the server site, then the lockd sends a SIGLOST to the process holding that lock.

Administrators can make changes to the startup parameters for lockd by logging in as root and editing the /etc/default/nfs file (see nfs(4)). Administrators can also make changes by using the setoncenv command.


lockd recognizes the following options and command-line arguments:

-g graceperiod

Deprecated in favor of the LOCKD_GRACE_PERIOD parameter in the NFS default file, which is equivalent. Specify the number of seconds that all clients (both NLM and NFSv4) have to reclaim locks after the server reboots. This option also controls the NFSv4 lease interval. The default value is 90 seconds.

-l listen_min_backlog

Specify the listener backlog, listen_min_backlog, which is the number of connect requests that are queued and waiting to be processed before new connect requests begin to get dropped.

-t timeout

Specify the number of seconds to wait before retransmitting a lock request to the remote server. The default value is 5 seconds. Equivalent to the LOCKD_RETRANSMIT_TIMEOUT parameter in the NFS default file.


Specify the maximum number of concurrent threads that the server can handle. This concurrency is achieved by up to nthreads threads created as needed in the kernel. nthreads should be based on the load expected on this server. If nthreads is not specified, the maximum number of concurrent threads will default to 20. Equivalent to the LOCKD_SERVERS parameter in the NFS default file.


A directory service that provides service name data base support must have the following service entries in its database:

lockd 4045/udp # NFS lockd daemon/manager for udp lockd 4045/tcp # NFS lockd daemon/manager for tcp


lockd was developed by Sun Microsystems, Inc. and HP.

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