NAME
rpc.statd —
host status monitoring
daemon
SYNOPSIS
rpc.statd |
[-d] |
DESCRIPTION
Therpc.statd utility is a daemon which co-operates 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 re-starts, when the rpc.statd
re-starts, it will notify all of the hosts which were being monitored at the
time of the crash.
The following option is available:
-d- Cause 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. Error conditions are logged irrespective of this option, using level LOG_ERR.
The rpc.statd utility must NOT be invoked
by inetd(8) because the protocol assumes that the daemon will run from
system start time. Instead, it should be run from
rc(8) after the network has been started.
FILES
- /var/db/statd.status
- non-volatile record of currently monitored hosts.
- /usr/include/rpcsvc/sm_inter.x
- RPC protocol specification used by local applications to register monitoring requests.
SEE ALSO
STANDARDS
The implementation is based on the specification in X/Open CAE Specification C218, "Protocols for X/Open PC Interworking: XNFS, Issue 4", ISBN 1 872630 66 9
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 re-try notification attempts at frequent intervals for 10 minutes, then hourly, and finally gives up after 24 hours.
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.
The current implementation uses more than 1Kbyte per monitored host in the status file (and also in VM). This may be inefficient for NFS servers with large numbers of clients.