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mfschunkserver

Start, restart or stop MooseFS chunkserver process.

This page reproduces the manual page mfschunkserver(8) as the product ships it: the text man mfschunkserver 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​

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

mfschunkserver -v

mfschunkserver -h

Description​

mfschunkserver is the data server 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 mfschunkserver.cfg in system configuration directory)

  • -o OPTIONOVERRIDE
    override a config option - see NOTES

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

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

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

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

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

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

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

    • kill
      Send an immediate termination signal to chunkserver process.

    • restore
      Not implemented.

Files​

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

  • mfshdd.cfg
    list of directories (mountpoints) used for MooseFS storage; refer to mfshdd.cfg(5) manual for details

  • .mfschunkserver.lock
    lock file of running MooseFS chunkserver process (created in data directory)

  • chunkserverid.mfs
    chunkserver ID, assigned by MooseFS master during first connection (created in data directory)

  • csstats.mfs
    chunkserver charts stats (created in data directory)

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

  • .lock
    file created on each volume(path) the chunkserver uses for chunk storage (each entry from mfshdd.cfg), another chunkserver process will not use a volume(path) with this file

  • .metaid
    file created on each volume(path) the chunkserver uses for chunk storage (each entry from mfshdd.cfg), contains MooseFS instance ID, if this ID is different than ID sent by the master, the chunksever will not use (ignore) this volume(path)

  • .chunkdb
    file created on each volume(path) the chunkserver uses for chunk storage (each entry from mfshdd.cfg) during graceful shutdown, the chunkserver process will attempt to use this file as chunk cache the next time it starts up, but only, if its mtime/ctime is not older than that of any folder with chunks; you can delete this file before chunkserver startup to force a full scan for chunks

Notes​

All MooseFS daemons, including mfschunkserver, 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 (mfschunkserver.cfg for mfschunkserver process).

All possible configuration options are described in the manpage for the mfschunkserver.cfg(5) file. Options provided in commandline are the same as in the config file (e.g. running the mfschunkserver with -o HDD_TEST_SPEED=5 will change this chunkserver's background chunk tests speed to 5 MiB/s). Options provided in environment must be prefixed with "MFSCFG_" (e.g setting MFSCFG_HDD_TEST_SPEED to 5 in environment will change this chunkserver's background chunk tests speed to 5 Mb/s if HDD_TEST_SPEED is not overriden in commandline).

See also​

mfsmaster(8), mfsmount(8), mfschunkserver.cfg(5), mfshdd.cfg(5)