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mfsmetalogger

Start, restart or stop MooseFS metalogger process.

This page reproduces the manual page mfsmetalogger(8) as the product ships it: the text man mfsmetalogger prints on a machine where the packages are installed. It is not edited here, and where it disagrees with the rest of this documentation, the documentation is the side kept against the sources. What the subject is: Command line tools.

Synopsis​

mfsmetalogger [-f] [-d] [-u] [-n] [-t LOCKTIMEOUT] [-c CFGFILE] [-o OPTIONOVERRIDE] [ACTION]

mfsmetalogger -v

mfsmetalogger -h

Description​

mfsmetalogger is the metadata replication module of MooseFS.

Options​

  • -v
    print version information and exit

  • -h
    print usage information and exit

  • -f
    run in foreground, don't daemonize

  • -d
    run with dangerous options (names: DANGEROUS_*)

  • -u
    log undefined configuration values (when default is assumed)

  • -n
    do not attempt to increase limit of core dump size

  • -t LOCKTIMEOUT
    how long to wait for lockfile (in seconds; default is 1800 seconds)

  • -c CFGFILE
    specify alternative path of configuration file (default is mfsmetalogger.cfg in system configuration directory)

  • -o OPTIONOVERRIDE
    override a config option - see NOTES

  • ACTION
    tells metalogger to perform one of the following actions:

    • start
      (default action) Start metalogger process if the process is not already running, otherwise display error message.

    • stop
      Stop metalogger process if the process is running, otherwise display error message.

    • restart
      If the metalogger process is running, restart it, if it's not running, start it.

    • reload
      Send a signal to metalogger process to reload config files.

    • info
      Send a signal to metalogger process to dump debug information file in working directory.

    • test
      Displays "mfsmetalogger pid: PID" if the metalogger is running (and return 0) or "mfsmetalogger is not running" otherwise (and return 1).

    • kill
      Send an immediate termination signal to metalogger process.

    • restore
      Not implemented.

Files​

  • mfsmetalogger.cfg
    configuration file for MooseFS metalogger process; refer to mfsmetalogger.cfg(5) manual for details

  • .mfsmetalogger.lock
    lock file of running MooseFS metalogger process (created in data directory)

  • changelog_ml.*.mfs
    MooseFS filesystem metadata change logs (backup of master change log files, recorded from single changelogs by metalogger, created in data directory)

  • changelog_ml_back.*.mfs
    MooseFS filesystem metadata change logs (backup of master change log files, downloaded entirely from master, created in data directory)

  • metadata_ml.mfs.back[.*]
    Copies of complete metadata.mfs.back[.*] files from MooseFS master (downloaded entirely from master, created in data directory)

  • .mfsmetalogger_info.txt
    metalogger info file, created by sending the process INFO signal, with work parameters that can be used for debugging/support purposes (created in data directory)

Notes​

All MooseFS daemons, including mfsmetalogger, can read configuration options from 3 sources. These sources are, in order from the most important, to the least important:

  • option overrides provided in commandline as arguments
  • options defined in environment variables
  • options defined in the daemon's main config file (mfsmetalogger.cfg for mfsmetalogger process).

All possible configuration options are described in the manpage for the mfsmetalogger.cfg(5) file. Options provided in commandline are the same as in the config file (e.g. running the mfsmetalogger with -o MASTER_TIMEOUT=15 will change the metalogger's timeout in the connection with master to 15 seconds). Options provided in environment must be prefixed with "MFSCFG_" (e.g setting MFSCFG_MASTER_TIMEOUT to 15 in environment will change the metalogger's timeout in the connection with master to 15 seconds if MASTER_TIMEOUT is not overriden in commandline).

See also​

mfsmaster(8), mfsmetalogger.cfg(5)