Provided by: lizardfs-master_3.12.0+dfsg-4ubuntu1_amd64 
NAME
mfsmaster.cfg - main configuration file for mfsmaster
DESCRIPTION
The file mfsmaster.cfg contains configuration of LizardFS metadata server process.
SYNTAX
Syntax is:
OPTION = VALUE
Lines starting with # character are ignored.
OPTIONS
Configuration options:
PERSONALITY
Current personality of this instance of metadata server. Valid values are master,
shadow and ha-cluster-managed. If installation is managed by an HA cluster the only
valid value is ha-cluster-managed, otherwise the only valid values are master and
shadow, in which case only one metadata server in LizardFS shall have master
personality.
PERSONALITY = master means that this instance of metadata server acts as main metadata
server govering all file system metadata modifications.
PERSONALITY = shadow means that this instance of metadata server acts as backup
metadata server ready for immediate deployment as new master in case of current master
failure.
Metadata server personality can be changed at any moment as long as one changes
personality from shadow to master, changing personality the other way around is
forbidden.
PERSONALITY = ha-cluster-managed means that this instance is managed by HA cluster,
server runs in shadow mode as long as its not remotly promoted to master.
DATA_PATH
where to store metadata files and lock file
WORKING_USER
user to run daemon as
WORKING_GROUP
group to run daemon as (optional - if empty then default user group will be used)
SYSLOG_IDENT
name of process to place in syslog messages (default is mfsmaster)
LOCK_MEMORY
whether to perform mlockall() to avoid swapping out mfsmaster process (default is 0,
i.e. no)
NICE_LEVEL
nice level to run daemon with (default is -19 if possible; note: process must be
started as root to increase priority)
EXPORTS_FILENAME
alternative name of mfsexports.cfg file
TOPOLOGY_FILENAME
alternative name of mfstopology.cfg file
CUSTOM_GOALS_FILENAME
alternative name of mfsgoals.cfg file
PREFER_LOCAL_CHUNKSERVER
If a client mountpoint has a local chunkserver, and a given chunk happens to reside
locally, then mfsmaster will list the local chunkserver first. However, when the local
client mount is issuing many read(s)/write(s), to many local chunks, these requests
can overload the local chunkserver and disk subsystem. Setting this to 0(the default
is 1) means that remote chunkservers will be considered as equivalent to the local
chunkserver.
This is useful when the network is faster than the disk, and when there is high-IO
load on the client mountpoints.
BACK_LOGS
number of metadata change log files (default is 50)
BACK_META_KEEP_PREVIOUS
number of previous metadata files to be kept (default is 1)
AUTO_RECOVERY
when this option is set (equals 1) master will try to recover metadata from changelog
when it is being started after a crash; otherwise it will refuse to start and
mfsmetarestore should be used to recover the metadata (default is 0)
REPLICATIONS_DELAY_INIT
DEPRECATED - see OPERATIONS_DELAY_INIT
REPLICATIONS_DELAY_DISCONNECT
DEPRECATED - see OPERATIONS_DELAY_DISCONNECT
OPERATIONS_DELAY_INIT
initial delay in seconds before starting chunk operations (default is 300)
OPERATIONS_DELAY_DISCONNECT
chunk operations delay in seconds after chunkserver disconnection (default is 3600)
MATOML_LISTEN_HOST
IP address to listen on for metalogger connections (* means any)
MATOML_LISTEN_PORT
port to listen on for metalogger connections (default is 9419)
MATOML_LOG_PRESERVE_SECONDS
how many seconds of change logs have to be preserved in memory (default is 600; note:
logs are stored in blocks of 5k lines, so sometimes real number of seconds may be
little bigger; zero disables extra logs storage)
MATOCS_LISTEN_HOST
IP address to listen on for chunkserver connections (* means any)
MATOCS_LISTEN_PORT
port to listen on for chunkserver connections (default is 9420)
MATOCL_LISTEN_HOST
IP address to listen on for client (mount) connections (* means any)
MATOCL_LISTEN_PORT
port to listen on for client (mount) connections (default is 9421)
MATOTS_LISTEN_HOST
IP address to listen on for tapeserver connections (* means any)
MATOTS_LISTEN_PORT
Port to listen on for tapeserver connections (default is 9424)
CHUNKS_LOOP_MAX_CPS
Chunks loop shouldn’t check more chunks per seconds than given number (default is
100000)
CHUNKS_LOOP_MIN_TIME
Chunks loop will check all chunks in specified time (default is 300) unless
CHUNKS_LOOP_MAX_CPS will force slower execution.
CHUNKS_LOOP_PERIOD
Time in milliseconds between chunks loop execution (default is 1000).
CHUNKS_LOOP_MAX_CPU
Hard limit on CPU usage by chunks loop (percentage value, default is 60).
CHUNKS_SOFT_DEL_LIMIT
Soft maximum number of chunks to delete on one chunkserver (default is 10)
CHUNKS_HARD_DEL_LIMIT
Hard maximum number of chunks to delete on one chunkserver (default is 25)
CHUNKS_WRITE_REP_LIMIT
Maximum number of chunks to replicate to one chunkserver (default is 2)
CHUNKS_READ_REP_LIMIT
Maximum number of chunks to replicate from one chunkserver (default is 10)
ENDANGERED_CHUNKS_PRIORITY
Percentage of endangered chunks that should be replicated with high priority. Example:
when set to 0.2, up to 20% of chunks served in one turn would be extracted from
endangered priority queue. When set to 1 (max), no other chunks would be processed as
long as there are any endangered chunks in the queue (not advised) (default is 0, i.e.
there is no overhead for prioritizing endangered chunks).
ENDANGERED_CHUNKS_MAX_CAPACITY
Max capacity of endangered chunks queue. This value can limit memory usage of master
server if there are lots of endangered chunks in the system. This value is ignored if
ENDANGERED_CHUNKS_PRIORITY is set to 0. (default is 1Mi, i.e. no more than 1Mi chunks
will be kept in a queue).
ACCEPTABLE_DIFFERENCE
A maximum difference between disk usage on chunkservers that doesn’t trigger chunk
rebalancing (default is 0.1, i.e. 10%).
CHUNKS_REBALANCING_BETWEEN_LABELS
When balancing disk usage, allow moving chunks between servers with different labels
(default is 0, i.e. chunks will be moved only between servers with the same label).
REJECT_OLD_CLIENTS
Reject mfsmounts older than 1.6.0 (0 or 1, default is 0). Note that mfsexports access
control is NOT used for those old clients.
GLOBALIOLIMITS_FILENAME
Configuration of global I/O limits (default is no I/O limiting)
GLOBALIOLIMITS_RENEGOTIATION_PERIOD_SECONDS
How often mountpoints will request bandwidth allocations under constant, predictable
load (default is 0.1)
GLOBALIOLIMITS_ACCUMULATE_MS
After inactivity, no waiting is required to transfer the amount of data equivalent to
normal data flow over the period of that many milliseconds (default is 250)
METADATA_CHECKSUM_INTERVAL
how often metadata checksum shall be sent to backup servers (default is: every 50
metadata updates)
METADATA_CHECKSUM_RECALCULATION_SPEED
how fast should metadata be recalculated in background (default : 100 objects per
function call)
DISABLE_METADATA_CHECKSUM_VERIFICATION
should checksum verification be disabled while applying changelog
NO_ATIME
when this option is set to 1 inode access time is not updated on every access,
otherwise (when set to 0) it is updated (default is 0)
METADATA_SAVE_REQUEST_MIN_PERIOD
minimal time in seconds between metadata dumps caused by requests from shadow masters
(default is 1800)
SESSION_SUSTAIN_TIME
Time in seconds for which client session data (e.g. list of open files) should be
sustained in the master server after connection with the client was lost. Values
between 60 and 604800 (one week) are accepted. (default is 86400)
USE_BDB_FOR_NAME_STORAGE
When this option is set to 1 Berkley DB is used for storing file/directory names in
file (DATA_PATH/name_storage.db). By default all strings are kept in system memory.
(default is 0)
BDB_NAME_STORAGE_CACHE_SIZE
Size of memory cache (in MB) for file/directory names used by Berkeley DB storage.
(default is 10)
AVOID_SAME_IP_CHUNKSERVERS
When this option is set to 1, process of selecting chunkservers for chunks will try to
avoid using those that share the same ip. (default is 0)
REDUNDANCY_LEVEL
minimum number of required redundant chunk parts that can be lost before chunk becomes
endangered (default is 0)
SNAPSHOT_INITIAL_BATCH_SIZE
This option can be used to specify initial number of snapshotted nodes that will be
atomically cloned before enqueuing the task for execution in fixed-sized batches.
(default is 1000)
SNAPSHOT_INITIAL_BATCH_SIZE_LIMIT
This option specifies the maximum initial batch size set for snapshot request.
(default is 10000)
FILE_TEST_LOOP_MIN_TIME Test files loop will try to check all files in specified time in
seconds (default is 3600). It’s possible for the loop to take more time if the master
server is busy or the machine doesn’t have enough processing power to make all the needed
calculations.
Options below are mandatory for all Shadow instances:
MASTER_HOST
address of the host running LizardFS metadata server that currently acts as master
MASTER_PORT
port number where LizardFS metadata server currently running as master listens for
connections from 'shadow’s and metaloggers (default is 9420)
MASTER_RECONNECTION_DELAY
delay in seconds before trying to reconnect to metadata server after disconnection
(default is 1)
MASTER_TIMEOUT
timeout (in seconds) for metadata server connections (default is 60)
LOAD_FACTOR_PENALTY
When set, percentage of load will be added to chunkserver disk usage to determine most
fitting chunkserver. Heavy loaded chunkservers will be picked for operations less
frequently. (default is 0, correct values are in range from 0 to 0.5)
NOTES
Chunks in master are tested in loop. Speed (or frequency) is regulated by two options
CHUNKS_LOOP_MIN_TIME and CHUNKS_LOOP_MAX_CPS. First defines minimal time of the loop and
second maximal number of chunk tests per second. Typically at the beginning, when number
of chunks is small, time is constant, regulated by CHUNK_LOOP_MIN_TIME, but when number of
chunks became bigger then time of loop can increase according to CHUNKS_LOOP_MAX_CPS.
Deletion limits are defined as soft and hard limit. When number of chunks to delete
increases from loop to loop then current limit can be temporary increased above soft
limit, but never above hard limit.
COPYRIGHT
Copyright 2008-2009 Gemius SA, 2013-2017 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
mfsmaster(8), mfsexports.cfg(5), mfstopology.cfg(5)
01/19/2020 MFSMASTER.CFG(5)