1MFSMASTER(8)                                                      MFSMASTER(8)
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NAME

6       mfsmaster - start, restart or stop Lizard File System metadata server
7       process
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SYNOPSIS

10       mfsmaster [-f] [-c CFGFILE] [-u] [-d] [-t LOCKTIMEOUT] [ACTION]
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12       mfsmaster -s [-c CFGFILE]
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14       mfsmaster -v
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16       mfsmaster -h
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DESCRIPTION

19       mfsmaster is the metadata server program of Lizard File System.
20       Depending on parameters it can start, restart or stop LizardFS metadata
21       server process. Without any options it starts LizardFS metadata server,
22       killing previously run process if lock file exists.
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24       Metadata server can work in one of two modes (personalities):
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26        1. master
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28        2. shadow
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30       If metadata server works with master personality it acts as main
31       metadata server govering all file system metadata modifications. If
32       metadata server works with shadow personality it acts as backup
33       metadata server ready for immediate deployment as new master in case of
34       current master failure. Shadow only accepts connections from
35       lizardfs-admin, i.e. mfschunkserver, mfsmetalogger and mfsmount (the
36       client) are not allowed to connect to shadow instance.
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38       Current metadata server personality is defined in metadata server
39       configuration file and can be changed on the fly from shadow to master
40       by proper modification and reloading of its configuration file.
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42       Master and shadow are designed to run simultaneously in sync forever.
43       It is very unlikely but still (due to a memory corruption or a bug)
44       possible that after some time their metadata will somehow differ. Since
45       version 2.5.2 metadata checksum is maintained both by master and
46       shadow, in order to detect and fix possible metadata corruptions. In
47       case mismatch is detected shadow asks master to double check its
48       metadata and dump its current snapshot. After the metadata is dumped
49       and the checksum in master is recalculated shadow downloads the new
50       metadata snapshot, which should ensure that master and all shadows have
51       exactly the same metadata.
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53       SIGHUP (or reload ACTION) forces mfsmaster to reload all configuration
54       files.
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56       -v
57           print version information and exit
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59       -h
60           print usage information and exit
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62       -f
63           (deprecated, use start action instead) forcily run LizardFS master
64           process, without trying to kill previous instance (this option
65           allows to run LizardFS master if stale PID file exists)
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67       -s
68           (deprecated, use stop action instead) stop LizardFS master process
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70       -c CFGFILE
71           specify alternative path of configuration file (default is
72           mfsmaster.cfg in system configuration directory)
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74       -u
75           log undefined configuration values (when default is assumed)
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77       -d
78           run in foreground, don’t daemonize
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80       -t LOCKTIMEOUT
81           how long to wait for lockfile (default is 60 seconds)
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83       ACTION
84           is the one of start, stop, restart, reload, test, isalive or kill.
85           Default action is restart.
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FILES

88       mfsmaster.cfg
89           configuration file for LizardFS master process (see
90           mfsmaster.cfg(5) manual)
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92       mfsexports.cfg
93           LizardFS access control file (used with mfsmounts 1.6.0 or later,
94           see mfsexports.cfg(5) manual)
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96       mfstopology.cfg
97           Network topology definitions (see mfstopology.cfg(5) manual)
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99       mfsmaster.lock
100           PID file of running LizardFS master process
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102       .mfsmaster.lock
103           lock file of running LizardFS master process (created in data
104           directory)
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106       metadata.mfs, metadata.mfs.back
107           LizardFS filesystem metadata image
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109       changelog.*.mfs
110           LizardFS filesystem metadata change logs (merged into metadata.mfs
111           once per hour)
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113       data.stats
114           LizardFS master charts state
115

REPORTING BUGS

117       Report bugs to <contact@lizardfs.org>.
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120       Copyright 2008-2009 Gemius SA, 2013-2015 Skytechnology sp. z o.o.
121
122       LizardFS is free software: you can redistribute it and/or modify it
123       under the terms of the GNU General Public License as published by the
124       Free Software Foundation, version 3.
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126       LizardFS is distributed in the hope that it will be useful, but WITHOUT
127       ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
128       FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
129       for more details.
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131       You should have received a copy of the GNU General Public License along
132       with LizardFS. If not, see http://www.gnu.org/licenses/.
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SEE ALSO

135       mfsmetarestore(8), mfschunkserver(8), mfsmount(1), mfsmaster.cfg(5),
136       mfsexports.cfg(5), mfstopology.cfg(5), moosefs(7)
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140                                  01/26/2021                      MFSMASTER(8)
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