mfsmaster.cfg - main configuration file for mfsmaster
The file mfsmaster.cfg contains the configuration of the LizardFS metadata server process.
OPTION = VALUE
Lines starting with a # character are being ignored.
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.
- where to store metadata files and lock file
- user to run daemon as
- group to run daemon as (optional - if empty then the default user group will be used)
- name of the process to place in syslog messages (default is mfsmaster)
- whether to perform mlockall() to avoid swapping out mfsmaster process (default is 0, i.e. no)
- nice level to run daemon with (default is -19 if possible; note: process must be started as root to increase priority)
- alternative name of the mfsexports.cfg file
- alternative name of the mfstopology.cfg file
- alternative name of the mfsgoals.cfg file
- number of metadata change log files (default is 50)
- number of previous metadata files to be kept (default is 1)
- 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)
- DEPRECATED - see OPERATIONS_DELAY_INIT
- DEPRECATED - see OPERATIONS_DELAY_DISCONNECT
- initial delay in seconds before starting chunk operations (default is 300)
- chunk operations delay in seconds after chunkserver disconnection (default is 3600)
- IP address to listen on for metalogger connections (* means any)
- port to listen on for metalogger connections (default is 9419)
- 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)
- IP address to listen on for chunkserver connections (* means any)
- port to listen on for chunkserver connections (default is 9420)
- IP address to listen on for client (mount) connections (* means any)
- port to listen on for client (mount) connections (default is 9421)
- IP address to listen on for tapeserver connections (* means any)
- Port to listen on for tapeserver connections (default is 9424)
- Chunks loop shouldn*t check more chunks per seconds than given number (default is 100000)
- Chunks loop will check all chunks in specified time (default is 300) unless CHUNKS_LOOP_MAX_CPS will force slower execution.
- Time in milliseconds between chunks loop execution (default is 1000).
- Hard limit on CPU usage by chunks loop (percentage value, default is 60).
- Soft maximum number of chunks to delete on one chunkserver (default is 10)
- Hard maximum number of chunks to delete on one chunkserver (default is 25)
- Maximum number of chunks to replicate to one chunkserver (default is 2)
- Maximum number of chunks to replicate from one chunkserver (default is 10)
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).
- 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).
- The maximum difference between disk usage on chunkservers that doesn*t trigger chunk rebalancing (default is 0.1, i.e. 10%).
- 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 mfsmounts older than 1.6.0 (0 or 1, default is 0). Note that mfsexports access control is NOT used for those old clients.
- Configuration of global I/O limits (default is no I/O limiting)
- How often mountpoints will request bandwidth allocations under constant, predictable load (default is 0.1)
- 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)
- how often metadata checksum shall be sent to backup servers (default is: every 50 metadata updates)
- how fast should metadata be recalculated in the background (default : 100 objects per function call)
- should checksum verification be disabled while applying changelog
- 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)
- minimal time in seconds between metadata dumps caused by requests from shadow masters (default is 1800)
- 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)
- 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)
- 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:
- address of the host running LizardFS metadata server that currently acts as master
- port number where LizardFS metadata server currently running as master listens for connections from shadows and metaloggers (default is 9420)
- delay in seconds before trying to reconnect to metadata server after disconnection (default is 1)
- timeout (in seconds) for metadata server connections (default is 60)
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.
Copyright 2008-2009 Gemius SA, 2013-2016 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/>.
mfsmaster(8), mfsexports.cfg(5), mfstopology.cfg(5)