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watchdogtimerd(8)                          System Manager's Manual                         watchdogtimerd(8)

NAME
     watchdogtimerd -- Mac OS X Server automatic reboot daemon (hardware watchdog tickler)

SYNOPSIS
     watchdogtimerd [-d | -n | -R] [-i interval] [-c count] [-L facility]

     watchdogtimerd [-h | -v]

DESCRIPTION
     watchdogtimerd is indirectly responsible for rebooting the server hardware if the machine hangs or pan-ics. panics.
     ics. When watchdogtimerd runs on supported hardware, it periodically resets the hardware watchdog
     timer.  If the timer ever expires, the power management unit forces a hard reboot.  Automatic reboot is
     disabled when watchdogtimerd quits cleanly, so it is imperative watchdogtimerd be terminated by sending
     a termination signal (SIGTERM), NOT a kill signal (SIGKILL)!

     watchdogtimerd is typically launched at boot time under the control of launchd(8) using the job label
     com.apple.watchdogtimerd.

OPTIONS
     The following options are available:
     -c count
     --cycles=count       Reboot the machine if the timer has not been reset for count intervals. This
                          option is primarily used when debugging.  Valid range of values is 3 through 480.
                          Default is 10 with most configurations, resulting in a reboot within five minutes
                          after failure. If the kernel's boot-args contained the "_panicd_ip" directive to
                          enable panic dumps (as noted in the referenced Tech Note below), the default is
                          raised to 30, resulting in a reboot after fifteen minutes to allow enough time for
                          the kernel to send the dump information.

     -d
     --debug              Print log strings to the terminal.

     -h
     --help               Print usage summary and exit.

     -i interval
     --interval=interval  Reset the watchdog timer every interval seconds. This option is primarily used
                          when debugging.  Valid range of values is 1 through 30. Default is 30.

     -L facility          Enable logging to syslog(8) using the specified facility.  The following values
                          for facility are supported: daemon (the default), user, local[_-7].  (See
                          syslog.conf(5) for their meanings.) This is equivalent to --syslog.

     -n
     --no-run             Print log information to the terminal and quit after validating the hardware
                          watchdog timer.

     -R
     --reboot             Force a hard reboot by initializing the watchdog timer to (count * interval) sec-onds seconds
                          onds and terminating.

     --syslog=facility    Enable logging to syslog(8) using the specified facility.  The following values
                          for facility are supported: daemon (the default), auth, user, local[_-7].  (See
                          syslog.conf(5) for their meanings.) This is equivalent to -L.

     -v
     --version            Print build version and exit.


FILES & FOLDERS
     /usr/sbin/watchdogtimerd
           -   daemon
     /System/Library/LaunchDaemons/com.apple.watchdogtimerd.plist
           -   launchd(8) configuration file.

DIAGNOSTICS
     The watchdogtimerd utility exits 0 on success, and >0 if an error occurs.  The following table lists
     possible exit codes, their equivalent constants in sysexits(3), and their corresponding failure condi-tion. condition.
     tion.

           code    constant          failure condition
           64      EX_USAGE          invalid arguments
           69      EX_UNAVAILABLE    automatic reboot timer unavailable
           77      EX_NOPERM         insufficient permissions

     Could not access automatic reboot timer.  The executing machine does not support a hardware watchdog
     timer.

     Invalid interval.  Valid intervals range from 1 to 30.

     Invalid number of cycles.  Valid cycles range from 3 to 480.

     Unable to raise process priority.  watchdogtimerd was unable to raise its priority. This may result in
     inadvertant reboots if other (typically real-time) processes consume all available cycles.

     watchdogtimerd must be executed as root.  Because watchdogtimerd controls system-wide resources, it
     must be executed by the root user.

SEE ALSO
     sysexits(3), syslog.conf(5), launchctl(8), launchd(8), syslogd(8)

     Apple's technical note TN2118: Kernel Core Dumps <http://developer.apple.com/technotes/tn2004/
     tn2118.html>  describes how to set up a crash dump server and how to send dumps from panicked machines.
     These instructions allow a site to record kernel panics for debugging or analysis while leveraging  the
     higher  service  availability  provided by watchdogtimerd.  This approach is recommended for most sites
     instead of increasing the time before forcing a reboot. (As noted in the OPTIONS section,  the  minimum
     reboot time is extended if such dumping is configured.)

KNOWN ISSUES
     None identified at this time.

HISTORY
     watchdogtimerd replaces the hardware watchdog timer servicing of watchdog(8).

     The pressing question used to be, "Who watches the watchmen?"  Now we know: launchd(8).

Mac OS X Server 10.6                            May 12, 2008                            Mac OS X Server 10.6