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MFSMASTER(8) | MFSMASTER(8) |
NAME¶
mfsmaster - start, restart or stop Lizard File System metadata server processSYNOPSIS¶
mfsmaster [ -f] [-c CFGFILE] [-u] [-d] [-t LOCKTIMEOUT] [ACTION]
mfsmaster -s [-c CFGFILE]
mfsmaster -v
mfsmaster -h
DESCRIPTION¶
mfsmaster 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): 1.master
2.shadow
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 instance.
Current metadata server personality is defined in metadata server configuration
file and can be changed on the fly from shadow to master by
proper modification and reloading of its configuration file.
Master and shadow 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 and
shadow, in order to detect and fix possible metadata corruptions. In
case mismatch is detected shadow asks master 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
same metadata.
SIGHUP (or reload ACTION) forces mfsmaster to reload all
configuration files.
-v
print version information and exit
-h
print usage information and exit
-f
(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)
-s
(deprecated, use stop action instead) stop
LizardFS master process
-c CFGFILE
specify alternative path of configuration file (default
is mfsmaster.cfg in system configuration directory)
-u
log undefined configuration values (when default is
assumed)
-d
run in foreground, don’t daemonize
-t LOCKTIMEOUT
how long to wait for lockfile (default is 60
seconds)
ACTION
is the one of start, stop, restart,
reload, test, isalive or kill. Default action is
restart.
FILES¶
mfsmaster.cfgconfiguration file for LizardFS master process (see
mfsmaster.cfg(5) manual)
mfsexports.cfg
LizardFS access control file (used with mfsmounts
1.6.0 or later, see mfsexports.cfg(5) manual)
mfstopology.cfg
Network topology definitions (see
mfstopology.cfg(5) manual)
mfsmaster.lock
PID file of running LizardFS master process
.mfsmaster.lock
lock file of running LizardFS master process (created in
data directory)
metadata.mfs, metadata.mfs.back
LizardFS filesystem metadata image
changelog.*.mfs
LizardFS filesystem metadata change logs (merged into
metadata.mfs once per hour)
data.stats
LizardFS master charts state
REPORTING BUGS¶
Report bugs to <contact@lizardfs.org>.COPYRIGHT¶
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/.SEE ALSO¶
mfsmetarestore(8), mfschunkserver(8), mfsmount(1), mfsmaster.cfg(5), mfsexports.cfg(5), mfstopology.cfg(5), moosefs(7)10/27/2016 |