RPC.LOCKD(8) System Manager's Manual RPC.LOCKD(8)

rpc.lockd — NFS file locking daemon

rpc.lockd [-d debug_level] [-g grace_period] [-x host_monitor_cache_period]

The rpc.lockd utility provides monitored and unmonitored file and record locking services in an NFS environment. To monitor the status of hosts requesting locks, the locking daemon typically operates in conjunction with rpc.statd(8).

The rpc.lockd utility runs whenever its services are needed to support either the NFS server (see nfsd(8)) or the NFS client (an NFS file system on which file locking requests have been made). The daemon will remain running until a short time after its services are no longer needed to support either the NFS client or NFS server. rpc.lockd will also make sure that the statd service (on which it depends) is running.

The following is a list of command line options that are available. However, since rpc.lockd is normally started by launchd(8), configuration of these options should be controlled using the equivalent settings in the NFS configuration file. See nfs.conf(5) for a list of tunable parameters.

The -d option causes debugging information to be written to syslog, recording all RPC transactions to the daemon. These messages are logged with level LOG_DEBUG and facility LOG_DAEMON. Specifying a debug_level of 1 results in the generation of one log line per protocol operation. Higher debug levels can be specified, causing display of operation arguments and internal operations of the daemon.
The -g option allows to specify the grace period (in seconds). During the grace period rpc.lockd only accepts requests from hosts which are reinitialising locks which existed before the server restart. Default is 45 seconds.
The -x option tells rpc.lockd how long to cache state records for monitored hosts. Setting it to zero will disable the cache which will make lock and unlock requests from a single client more expensive because of additional interaction with the client's statd. The default cache time is 60 seconds.

Error conditions are logged to syslog, irrespective of the debug level, using log level LOG_ERR and facility LOG_DAEMON.

/var/run/lockd.pid
The pid of the current lockd daemon.
/System/Library/LaunchDaemons/com.apple.lockd.plist
The lockd service's property list file for launchd(8).
/usr/include/rpcsvc/nlm_prot.x
RPC protocol specification for the network lock manager protocol.

nfs.conf(5), rpc.statd(8), syslog(3), launchd(8)

The current implementation serialises locks requests that could be shared.

The implementation is based on the specification in Protocols for X/Open PC Interworking: XNFS, Issue 4, X/Open CAE Specification C218, ISBN 1 872630 66 9.

A version of rpc.lockd appeared in SunOS 4.

January 9, 2007 macOS 15.0