mfsmaster.cfg(5)

NAME

mfsmaster.cfg - main configuration file for mfsmaster

DESCRIPTION

The file mfsmaster.cfg contains the configuration of the LizardFS metadata server process.

SYNTAX

OPTION = VALUE

Lines starting with a # character are being ignored.

OPTIONS

Configuration options:

PERSONALITY

Current personality of this instance of the metadata server. Valid values are master, shadow and ha-cluster-managed. If the 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 the metadata server acts as backup metadata server ready for immediate deployment as the new master in case of a failure of the current master.

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 the default user group will be used)
SYSLOG_IDENT
name of the 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 the mfsexports.cfg file
TOPOLOGY_FILENAME
alternative name of the mfstopology.cfg file
CUSTOM_GOALS_FILENAME
alternative name of the mfsgoals.cfg file
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 setting 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 the real number of seconds may be bit 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
The 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 the 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)

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 shadows 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)

Note

Chunks in master are tested in loop. Speed (or frequency) is regulated by the two options CHUNKS_LOOP_MIN_TIME and CHUNKS_LOOP_MAX_CPS. The first one defines the minimal time of the loop and the second one the maximal number of chunk tests per second. Typically at the beginning, when the number of chunks is small, time is constant, regulated by CHUNK_LOOP_MIN_TIME, but when the number of chunks becomes bigger then the time of the loop can increase according to CHUNKS_LOOP_MAX_CPS.

Deletion limits are defined as soft and hard limit. When the number of chunks to delete increases from loop to loop, the current limit can be temporary increased above the soft limit, but never above the hard limit.

REPORTING BUGS

Report bugs to <contact@lizardfs.org>.

SEE ALSO

mfsmaster(8), mfsexports.cfg(5), mfstopology.cfg(5)