mfsmaster - start, restart or stop Lizard File System metadata server process
mfsmaster [ -f] [-c CFGFILE] [-u] [-d] [-t LOCKTIMEOUT] [ACTION]
mfsmaster -s [-c CFGFILE]
is the metadata server program of Lizard File System. Depending
on parameters it can start, restart or stop LizardFS metadata server process.
Without any options it starts LizardFS metadata server, killing previously run
process if lock file exists.
Metadata server can work in one of two modes (personalities):
If metadata server works with master
personality it acts as main metadata
server govering all file system metadata modifications. If metadata server
works with shadow
personality it acts as backup metadata server ready
for immediate deployment as new master
in case of current master
failure. Shadow only accepts connections from lizardfs-admin, i.e.
mfschunkserver, mfsmetalogger and mfsmount (the client) are not allowed to
connect to shadow
Current metadata server personality is defined in metadata server configuration
file and can be changed on the fly from shadow
proper modification and reloading of its configuration file.
are designed to run simultaneously in sync
forever. It is very unlikely but still (due to a memory corruption or a bug)
possible that after some time their metadata will somehow differ. Since
version 2.5.2 metadata checksum is maintained both by master
, in order to detect and fix possible metadata corruptions. In
case mismatch is detected shadow
to double check its
metadata and dump its current snapshot. After the metadata is dumped and the
checksum in master
is recalculated shadow downloads the new metadata
snapshot, which should ensure that master and all shadows have exactly the
SIGHUP (or reload ACTION
) forces mfsmaster
to reload all
print version information and exit
print usage information and exit
(deprecated, use start action instead)
forcily run LizardFS master process, without trying to kill previous instance
(this option allows to run LizardFS master if stale PID file exists)
(deprecated, use stop action instead)
stop LizardFS master process
specify alternative path of configuration file
(default is mfsmaster.cfg in system configuration directory)
log undefined configuration values (when
default is assumed)
run in foreground, don’t
how long to wait for lockfile (default is 60
is the one of start, stop,
restart, reload, test, isalive or kill.
Default action is restart.
configuration file for LizardFS master process
(see mfsmaster.cfg(5) manual)
LizardFS access control file (used with
mfsmounts 1.6.0 or later, see mfsexports.cfg(5) manual)
Network topology definitions (see
PID file of running LizardFS master
lock file of running LizardFS master process
(created in data directory)
LizardFS filesystem metadata image
LizardFS filesystem metadata change logs
(merged into metadata.mfs once per hour)
LizardFS master charts state
Report bugs to <email@example.com>.
Copyright 2008-2009 Gemius SA, 2013-2015 Skytechnology sp. z o.o.
LizardFS is free software: you can redistribute it and/or modify it under the
terms of the GNU General Public License as published by the Free Software
Foundation, version 3.
LizardFS is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with
LizardFS. If not, see http://www.gnu.org/licenses/.
mfsmetarestore(8), mfschunkserver(8), mfsmount(1), mfsmaster.cfg(5),
mfsexports.cfg(5), mfstopology.cfg(5), moosefs(7)