downtimed - system downtime monitoring and reporting daemon
] [-d datadir
] [-l log
] [-p pidfile
daemon waits in the background, frequently updating a time
stamp file on the disk. If the daemon is killed with a signal associated with
a normal system shutdown procedure, it records the shutdown time on the disk.
When the daemon is restarted during the next boot process, it reports how long
the system was down and whether it was properly shut down or crashed. The
downtime report is output to the system log or to a specified log file. Also a
record is appended to the downtime database.
- Do not create nor update the downtime database.
- -d datadir
- The directory where the time stamp files as well as the
downtime database are located. The default directory is determined at
- Do not call daemon(3) to fork(2) to
background. Useful with modern system service managers such as
systemd(8), launchd(8) and others.
- -f timefmt
- Specify the time and date format to use when reporting
using strftime(3) syntax. The default is "%F %T".
- -l log
- Logging destination. If the argument contains a slash (/)
it is interpreted to be a path name to a log file, which will be created
if it does not exist already. Otherwise it is interpreted as a syslog
facility name. The default logging destination is "daemon" which
means that the messages are written to syslog with the daemon facility
- -p pidfile
- The location of the file which keeps track of the process
ID of the running daemon process. The system default location is
determined at compile time. May be disabled by specifying
- Normally fsync(2) is performed after each update of
the time stamp. This option disables the fsync(2). It reduces the
load on the disk system but makes the downtime measurement less
- -s sleep
- Defines how long to sleep between each update of the
on-disk time stamp file. More frequent updates result in more accurate
downtime reporting in the case of a system crash. Less frequent updates
decrease the amount of disk writes performed. The default is to sleep 15
seconds between each update. If you are using a flash memory based SSD or
other disk which has limited amount of write cycles per block, it might be
a good idea to set the sleep time to a higher value to prolong the
lifetime of the storage device.
- Display the program version number, copyright message and
the default settings.
- Close and re-open the output log. Use in case you want to
rotate the log file.
- SIGTERM and SIGINT
- Terminate gracefully. These signals signify that a graceful
system shutdown is in process.
The daemon exits 0 on success, and >0 if an error occurs.
The reporting accuracy in case of a system crash depends on how often the time
stamp is updated.
Finding out the system startup time is very operating system specific. If the
program does not have specific code to support your operating system, it
assumes that the system started when the daemon started.
Reporting is inaccurate if the system clock changes during system downtime or
startup process. Daylight saving time changes have no effect as all
calculations are done using UTC.
Copyright © 2009-2016 Janne Snabb. All rights reserved.
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