NAME

rpc.statd — host status monitoring daemon

SYNOPSIS

rpc.statd [-d]

rpc.statd [-d] -n

rpc.statd [-d] [-l | -L | -N hostname]

DESCRIPTION

The rpc.statd utility is a daemon which cooperates with rpc.statd daemons on other hosts to provide a status monitoring service. The daemon accepts requests from programs running on the local host (typically, rpc.lockd(8), the NFS file locking daemon) to monitor the status of specified hosts. If a monitored host crashes and restarts, the remote daemon will notify the local daemon, which in turn will notify the local program(s) which requested the monitoring service. Conversely, if this host crashes and restarts, the statd.notify service will be started to notify all of the hosts which were being monitored at the time of the crash.

The rpc.statd utility consists of two launchd(8)-controlled services. The statd.notify service is run whenever the system needs to notify remote hosts of a restart. The statd service is controlled by rpc.lockd(8) so that the rpc.statd daemon is running whenever rpc.lockd(8) is running.

The following is a list of command line options that are available. Note that since rpc.statd 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.

-d: Sets the logging level to the maximum. Note that finer grain control is available via the nfs.statd.verbose option in nfs.conf(5).
Logging is performed via syslog(3) using the LOG_DAEMON facility. By default, only messages up to priority LOG_WARNING are logged. Setting the verbose level to one will add LOG_NOTICE messages which includes logging failed mount attempts. A verbose level of two will increase the log level to LOG_INFO which includes logging successful mount attempts. A log level of three or more will add LOG_DEBUG messages and cause increasing amounts of debug information to be logged. The debug information exposes lots of information about rpc.statd's inner workings which is typically only useful to developers. Note: the syslog(8) configuration may need to be adjusted in order to see the increased verbosity.

The following command line option causes the daemon to run in the statd.notify notification service mode:

-n: Send SM_NOTIFY messages to notify any hosts of a restart.

The remaining command line options may be useful for viewing or modifying the contents of the status file. They do not start up any daemon or service.

-l: List each host (and its status) in the status file.
-L: List each host (and its status) in the status file and then continue to watch the file and report changes.
-N: Clear the "needs notification" status for hostname so the statd.notify service will no longer try to notify it.

FILES

/var/db/statd.status: non-volatile record of monitored hosts.
/var/run/statd.pid: The pid of the current statd daemon.
/var/run/statd.notify.pid: The pid of the current statd.notify daemon.
/System/Library/LaunchDaemons/com.apple.statd.notify.plist: The statd.notify service's property list file for launchd(8).
/usr/include/rpcsvc/sm_inter.x: RPC protocol specification used by local applications to register monitoring requests.

BUGS

There is no means for the daemon to tell when a monitored host has disappeared permanently (eg. catastrophic hardware failure), as opposed to transient failure of the host or an intermediate router. At present, it will pause and re-try notification at frequent intervals for 10 minutes, then hourly, and finally gives up after 24 hours. The -N option may be used to remove the "needs notification" status from such hosts.

The protocol requires that symmetric monitor requests are made to both the local and remote daemon in order to establish a monitored relationship. This is convenient for the NFS locking protocol, but probably reduces the usefulness of the monitoring system for other applications.

STANDARDS