1MFSMASTER.CFG(5)                                              MFSMASTER.CFG(5)
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NAME

6       mfsmaster.cfg - main configuration file for mfsmaster
7

DESCRIPTION

9       The file mfsmaster.cfg contains configuration of LizardFS metadata
10       server process.
11

SYNTAX

13       Syntax is:
14
15       OPTION = VALUE
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17       Lines starting with # character are ignored.
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OPTIONS

20       Configuration options:
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22       PERSONALITY
23           Current personality of this instance of metadata server. Valid
24           values are master, shadow and ha-cluster-managed. If installation
25           is managed by an HA cluster the only valid value is
26           ha-cluster-managed, otherwise the only valid values are master and
27           shadow, in which case only one metadata server in LizardFS shall
28           have master personality.
29
30           PERSONALITY = master means that this instance of metadata server
31           acts as main metadata server govering all file system metadata
32           modifications.
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34           PERSONALITY = shadow means that this instance of metadata server
35           acts as backup metadata server ready for immediate deployment as
36           new master in case of current master failure.
37
38           Metadata server personality can be changed at any moment as long as
39           one changes personality from shadow to master, changing personality
40           the other way around is forbidden.
41
42           PERSONALITY = ha-cluster-managed means that this instance is
43           managed by HA cluster, server runs in shadow mode as long as its
44           not remotly promoted to master.
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46       DATA_PATH
47           where to store metadata files and lock file
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49       WORKING_USER
50           user to run daemon as
51
52       WORKING_GROUP
53           group to run daemon as (optional - if empty then default user group
54           will be used)
55
56       SYSLOG_IDENT
57           name of process to place in syslog messages (default is mfsmaster)
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59       LOCK_MEMORY
60           whether to perform mlockall() to avoid swapping out mfsmaster
61           process (default is 0, i.e. no)
62
63       NICE_LEVEL
64           nice level to run daemon with (default is -19 if possible; note:
65           process must be started as root to increase priority)
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67       EXPORTS_FILENAME
68           alternative name of mfsexports.cfg file
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70       TOPOLOGY_FILENAME
71           alternative name of mfstopology.cfg file
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73       CUSTOM_GOALS_FILENAME
74           alternative name of mfsgoals.cfg file
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76       PREFER_LOCAL_CHUNKSERVER
77           If a client mountpoint has a local chunkserver, and a given chunk
78           happens to reside locally, then mfsmaster will list the local
79           chunkserver first. However, when the local client mount is issuing
80           many read(s)/write(s), to many local chunks, these requests can
81           overload the local chunkserver and disk subsystem. Setting this to
82           0(the default is 1) means that remote chunkservers will be
83           considered as equivalent to the local chunkserver.
84
85           This is useful when the network is faster than the disk, and when
86           there is high-IO load on the client mountpoints.
87
88       BACK_LOGS
89           number of metadata change log files (default is 50)
90
91       BACK_META_KEEP_PREVIOUS
92           number of previous metadata files to be kept (default is 1)
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94       AUTO_RECOVERY
95           when this option is set (equals 1) master will try to recover
96           metadata from changelog when it is being started after a crash;
97           otherwise it will refuse to start and mfsmetarestore should be used
98           to recover the metadata (default is 0)
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100       REPLICATIONS_DELAY_INIT
101           DEPRECATED - see OPERATIONS_DELAY_INIT
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103       REPLICATIONS_DELAY_DISCONNECT
104           DEPRECATED - see OPERATIONS_DELAY_DISCONNECT
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106       OPERATIONS_DELAY_INIT
107           initial delay in seconds before starting chunk operations (default
108           is 300)
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110       OPERATIONS_DELAY_DISCONNECT
111           chunk operations delay in seconds after chunkserver disconnection
112           (default is 3600)
113
114       MATOML_LISTEN_HOST
115           IP address to listen on for metalogger connections (* means any)
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117       MATOML_LISTEN_PORT
118           port to listen on for metalogger connections (default is 9419)
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120       MATOML_LOG_PRESERVE_SECONDS
121           how many seconds of change logs have to be preserved in memory
122           (default is 600; note: logs are stored in blocks of 5k lines, so
123           sometimes real number of seconds may be little bigger; zero
124           disables extra logs storage)
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126       MATOCS_LISTEN_HOST
127           IP address to listen on for chunkserver connections (* means any)
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129       MATOCS_LISTEN_PORT
130           port to listen on for chunkserver connections (default is 9420)
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132       MATOCL_LISTEN_HOST
133           IP address to listen on for client (mount) connections (* means
134           any)
135
136       MATOCL_LISTEN_PORT
137           port to listen on for client (mount) connections (default is 9421)
138
139       MATOTS_LISTEN_HOST
140           IP address to listen on for tapeserver connections (* means any)
141
142       MATOTS_LISTEN_PORT
143           Port to listen on for tapeserver connections (default is 9424)
144
145       CHUNKS_LOOP_MAX_CPS
146           Chunks loop shouldn’t check more chunks per seconds than given
147           number (default is 100000)
148
149       CHUNKS_LOOP_MIN_TIME
150           Chunks loop will check all chunks in specified time (default is
151           300) unless CHUNKS_LOOP_MAX_CPS will force slower execution.
152
153       CHUNKS_LOOP_PERIOD
154           Time in milliseconds between chunks loop execution (default is
155           1000).
156
157       CHUNKS_LOOP_MAX_CPU
158           Hard limit on CPU usage by chunks loop (percentage value, default
159           is 60).
160
161       CHUNKS_SOFT_DEL_LIMIT
162           Soft maximum number of chunks to delete on one chunkserver (default
163           is 10)
164
165       CHUNKS_HARD_DEL_LIMIT
166           Hard maximum number of chunks to delete on one chunkserver (default
167           is 25)
168
169       CHUNKS_WRITE_REP_LIMIT
170           Maximum number of chunks to replicate to one chunkserver (default
171           is 2)
172
173       CHUNKS_READ_REP_LIMIT
174           Maximum number of chunks to replicate from one chunkserver (default
175           is 10)
176
177       ENDANGERED_CHUNKS_PRIORITY
178           Percentage of endangered chunks that should be replicated with high
179           priority. Example: when set to 0.2, up to 20% of chunks served in
180           one turn would be extracted from endangered priority queue. When
181           set to 1 (max), no other chunks would be processed as long as there
182           are any endangered chunks in the queue (not advised) (default is 0,
183           i.e. there is no overhead for prioritizing endangered chunks).
184
185       ENDANGERED_CHUNKS_MAX_CAPACITY
186           Max capacity of endangered chunks queue. This value can limit
187           memory usage of master server if there are lots of endangered
188           chunks in the system. This value is ignored if
189           ENDANGERED_CHUNKS_PRIORITY is set to 0. (default is 1Mi, i.e. no
190           more than 1Mi chunks will be kept in a queue).
191
192       ACCEPTABLE_DIFFERENCE
193           A maximum difference between disk usage on chunkservers that
194           doesn’t trigger chunk rebalancing (default is 0.1, i.e. 10%).
195
196       CHUNKS_REBALANCING_BETWEEN_LABELS
197           When balancing disk usage, allow moving chunks between servers with
198           different labels (default is 0, i.e. chunks will be moved only
199           between servers with the same label).
200
201       REJECT_OLD_CLIENTS
202           Reject mfsmounts older than 1.6.0 (0 or 1, default is 0). Note that
203           mfsexports access control is NOT used for those old clients.
204
205       GLOBALIOLIMITS_FILENAME
206           Configuration of global I/O limits (default is no I/O limiting)
207
208       GLOBALIOLIMITS_RENEGOTIATION_PERIOD_SECONDS
209           How often mountpoints will request bandwidth allocations under
210           constant, predictable load (default is 0.1)
211
212       GLOBALIOLIMITS_ACCUMULATE_MS
213           After inactivity, no waiting is required to transfer the amount of
214           data equivalent to normal data flow over the period of that many
215           milliseconds (default is 250)
216
217       METADATA_CHECKSUM_INTERVAL
218           how often metadata checksum shall be sent to backup servers
219           (default is: every 50 metadata updates)
220
221       METADATA_CHECKSUM_RECALCULATION_SPEED
222           how fast should metadata be recalculated in background (default :
223           100 objects per function call)
224
225       DISABLE_METADATA_CHECKSUM_VERIFICATION
226           should checksum verification be disabled while applying changelog
227
228       NO_ATIME
229           when this option is set to 1 inode access time is not updated on
230           every access, otherwise (when set to 0) it is updated (default is
231           0)
232
233       METADATA_SAVE_REQUEST_MIN_PERIOD
234           minimal time in seconds between metadata dumps caused by requests
235           from shadow masters (default is 1800)
236
237       SESSION_SUSTAIN_TIME
238           Time in seconds for which client session data (e.g. list of open
239           files) should be sustained in the master server after connection
240           with the client was lost. Values between 60 and 604800 (one week)
241           are accepted. (default is 86400)
242
243       USE_BDB_FOR_NAME_STORAGE
244           When this option is set to 1 Berkley DB is used for storing
245           file/directory names in file (DATA_PATH/name_storage.db). By
246           default all strings are kept in system memory. (default is 0)
247
248       BDB_NAME_STORAGE_CACHE_SIZE
249           Size of memory cache (in MB) for file/directory names used by
250           Berkeley DB storage. (default is 10)
251
252       AVOID_SAME_IP_CHUNKSERVERS
253           When this option is set to 1, process of selecting chunkservers for
254           chunks will try to avoid using those that share the same ip.
255           (default is 0)
256
257       REDUNDANCY_LEVEL
258           minimum number of required redundant chunk parts that can be lost
259           before chunk becomes endangered (default is 0)
260
261       SNAPSHOT_INITIAL_BATCH_SIZE
262           This option can be used to specify initial number of snapshotted
263           nodes that will be atomically cloned before enqueuing the task for
264           execution in fixed-sized batches. (default is 1000)
265
266       SNAPSHOT_INITIAL_BATCH_SIZE_LIMIT
267           This option specifies the maximum initial batch size set for
268           snapshot request. (default is 10000)
269
270       FILE_TEST_LOOP_MIN_TIME Test files loop will try to check all files in
271       specified time in seconds (default is 3600). It’s possible for the loop
272       to take more time if the master server is busy or the machine doesn’t
273       have enough processing power to make all the needed calculations.
274
275       Options below are mandatory for all Shadow instances:
276
277       MASTER_HOST
278           address of the host running LizardFS metadata server that currently
279           acts as master
280
281       MASTER_PORT
282           port number where LizardFS metadata server currently running as
283           master listens for connections from 'shadow’s and metaloggers
284           (default is 9420)
285
286       MASTER_RECONNECTION_DELAY
287           delay in seconds before trying to reconnect to metadata server
288           after disconnection (default is 1)
289
290       MASTER_TIMEOUT
291           timeout (in seconds) for metadata server connections (default is
292           60)
293
294       LOAD_FACTOR_PENALTY
295           When set, percentage of load will be added to chunkserver disk
296           usage to determine most fitting chunkserver. Heavy loaded
297           chunkservers will be picked for operations less frequently.
298           (default is 0, correct values are in range from 0 to 0.5)
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NOTES

301       Chunks in master are tested in loop. Speed (or frequency) is regulated
302       by two options CHUNKS_LOOP_MIN_TIME and CHUNKS_LOOP_MAX_CPS. First
303       defines minimal time of the loop and second maximal number of chunk
304       tests per second. Typically at the beginning, when number of chunks is
305       small, time is constant, regulated by CHUNK_LOOP_MIN_TIME, but when
306       number of chunks became bigger then time of loop can increase according
307       to CHUNKS_LOOP_MAX_CPS.
308
309       Deletion limits are defined as soft and hard limit. When number of
310       chunks to delete increases from loop to loop then current limit can be
311       temporary increased above soft limit, but never above hard limit.
312
314       Copyright 2008-2009 Gemius SA, 2013-2017 Skytechnology sp. z o.o.
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316       LizardFS is free software: you can redistribute it and/or modify it
317       under the terms of the GNU General Public License as published by the
318       Free Software Foundation, version 3.
319
320       LizardFS is distributed in the hope that it will be useful, but WITHOUT
321       ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
322       FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
323       for more details.
324
325       You should have received a copy of the GNU General Public License along
326       with LizardFS. If not, see http://www.gnu.org/licenses/.
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SEE ALSO

329       mfsmaster(8), mfsexports.cfg(5), mfstopology.cfg(5)
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333                                  07/21/2022                  MFSMASTER.CFG(5)
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