3 .\" Copyright (c) 1995 A.R.Gordon, andrew.gordon@net-tel.co.uk
4 .\" All rights reserved.
6 .\" Redistribution and use in source and binary forms, with or without
7 .\" modification, are permitted provided that the following conditions
9 .\" 1. Redistributions of source code must retain the above copyright
10 .\" notice, this list of conditions and the following disclaimer.
11 .\" 2. Redistributions in binary form must reproduce the above copyright
12 .\" notice, this list of conditions and the following disclaimer in the
13 .\" documentation and/or other materials provided with the distribution.
14 .\" 3. All advertising materials mentioning features or use of this software
15 .\" must display the following acknowledgement:
16 .\" This product includes software developed by the University of
17 .\" California, Berkeley and its contributors.
18 .\" 4. Neither the name of the University nor the names of its contributors
19 .\" may be used to endorse or promote products derived from this software
20 .\" without specific prior written permission.
22 .\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
23 .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 .\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
26 .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36 .Dd September 19, 1995
41 .Nd host status monitoring daemon
49 is a daemon which co-operates with
51 daemons on other hosts to provide
52 a status monitoring service.
53 The daemon accepts requests from
54 programs running on the local host (typically,
56 the NFS file locking daemon) to monitor the status of specified
58 If a monitored host crashes and restarts, the remote daemon will
59 notify the local daemon, which in turn will notify the local program(s)
60 which requested the monitoring service.
61 Conversely, if this host crashes
62 and re-starts, when the
64 re-starts, it will notify all of the hosts which were being monitored
65 at the time of the crash.
67 The following option is available:
68 .Bl -tag -width indent
70 Cause debugging information to be written to syslog, recording
71 all RPC transactions to the daemon.
72 These messages are logged with level
73 LOG_DEBUG and facility LOG_DAEMON.
74 Error conditions are logged irrespective
75 of this option, using level LOG_ERR.
80 utility must NOT be invoked by
82 because the protocol assumes that the daemon will run from system start time.
83 Instead, it should be run from
85 after the network has been started.
87 .Bl -tag -width /usr/include/rpcsvc/sm_inter.x -compact
88 .It Pa /var/db/statd.status
89 non-volatile record of currently monitored hosts.
90 .It Pa /usr/include/rpcsvc/sm_inter.x
91 RPC protocol specification used by local applications to register monitoring requests.
98 There is no means for the daemon to tell when a monitored host has
99 disappeared permanently (e.g.\& catastrophic hardware failure), as opposed
100 to transient failure of the host or an intermediate router.
102 it will re-try notification attempts at frequent intervals for 10 minutes,
103 then hourly, and finally gives up after 24 hours.
105 The protocol requires that symmetric monitor requests are made to both
106 the local and remote daemon in order to establish a monitored relationship.
107 This is convenient for the NFS locking protocol, but probably reduces the
108 usefulness of the monitoring system for other applications.
110 The current implementation uses more than 1Kbyte per monitored host in
111 the status file (and also in VM).
112 This may be inefficient for NFS servers
113 with large numbers of clients.
115 The implementation is based on the specification in X/Open CAE Specification
116 C218, "Protocols for X/Open PC Interworking: XNFS, Issue 4", ISBN 1 872630 66 9