Ubuntu Manpages

mfschunkserver.cfg

main configuration file for mfschunkserver

The file mfschunkserver.cfg contains configuration of MooseFS chunkserver process.

Syntax is:

Lines starting with # character are ignored as comments.

Changes in this section require process restart.

user to run daemon as
group to run daemon as; optional value - if empty then default user group will be used
name of process to place in syslog messages; default is mfschunkserver
whether to perform mlockall() to avoid swapping out mfschunkserver process; default is 0, i.e. no
limit malloc arenas to given value - prevents server from using huge amount of virtual memory (Linux only, default is 4)
disable out of memory killer (Linux only, default is 1)
nice level to run daemon with; default is -19; note: process must be started as root to increase priority, if setting of priority fails, process retains the nice level it started with
set default umask for group and others (user has always 0); default is 027 - block write for group and block all for others
where to store daemon lock file
when set to one chunkserver will not abort start even when incorrect entries are found in 'mfshdd.cfg' file; default is 0 (do not start with invalid entries)
using mmap for allocation can slightly reduce ram usage and give a silight performance boost, but on certain architectures/kernels can lead to problems - especially on architectures with more than one physical CPU; default is 0

Changes in this section require only process reload.

alternate location/name of mfshdd.cfg file
Speed of background chunk tests in MB/s per disk (formally entry defined in mfshdd.cfg). Value can be given as a decimal number; default is 1.0
prevents from testing chunk integrity when last I/O (including test) was performed less than HDD_MIN_TEST_INTERVAL ago; default is 1 day; for value formatting see TIME
If possible use posix_fadvise(POSIX_DONTNEED) after each chunk test (but only if last I/O operation was performed more than HDD_FADVISE_MIN_TIME ago). Using zero will always perform posix_fadvise (flush cache) and using negative value will never flush cache after tests. This setting is valid only for systems that support posix_fadivise; default is 1 day; for value formatting see TIME
how much space should be left unused on each hard drive; number format: [0-9]*(.[0-9]*)?([kMGTPE]|[KMGTPE]i)?B? ; default is 256MiB; examples: 0.5GB, .5G, 2.56GiB, 1256M etc.
percent of total work time the chunkserver is allowed to spend on hdd space rebalancing; default is 20
maximum simultaneous writes per disk in high speed disk rebalance (0 means use standard rebalance; default is 0)
how many i/o errors (COUNT) to tolerate in given amount of seconds (PERIOD) on a single hard drive; if the number of errors exceeds this setting, the offending hard drive will be marked as damaged; defaults are 2 and 600
enables/disables fsync before chunk closing; default is 0 (off)
enables/disables sparsification (skip leading and trailing zeroz) during writing new block; default is 1 (on)
how many chunks should be created in one directory before moving to the next one; higher values are better with most OSes caching algorithms, low values lead to more even chunk distribution; default is 10000 which works best in most cases
how many hours duplicate chunks should be kept before deleting (default is one week); changing this value and reloading will reset the counter; for value formatting see TIME
maximum number of active workers and maximum number of idle workers; defaults are 250 and 40
minimum level of messages that will be reported by chunkserver; levels in order of importance: ERROR, WARNING, NOTICE, INFO, DEBUG (default is INFO)
reported messages of level lower than set by this option will be elevated to this level (i.e. if SYSLOG_MIN_LEVEL is set to DEBUG and SYSLOG_ELEVATE_TO is set to NOTICE, all INFO and DEBUG messages will be sent to syslog as NOTICE ; default is NOTICE)

Changes in this section require only process reload.

labels string defined as a set of letters (case insensitive) separated by coma or semicolon; default is empty - no labels
local address to use for master connections; default is *, i.e. default local address
MooseFS master host, IP is allowed only in single-master installations; default is mfsmaster
MooseFS master command port; default is 9420
(pro only) MooseFS master control port; default is 9419
timeout in seconds for master connections (if not 0); If this value is zero then chunkserver sets it initially to 10 and asks master for this value. default is 0 (ask master).
delay in seconds before trying to reconnect to master after disconnection (default is 5)
authentication string (used only when master requires authorization)
maximum number of chunks system will try to put in a single register message (default is 1000, limits 100-10000)

Changes in this section require only process reload.

IP address to listen on for client (mount) connections (* means any)
port to listen on for client (mount) connections (default is 9422)

For config variables that define time without requiring a single, specific unit, time can be defined as a number of seconds (integer) or a time period in one of two possible formats:

first format: #.#T where T is one of: s-seconds, m-minutes, h-hours, d-days or w-weeks; fractions of seconds will be rounded to full seconds

second format: #w#d#h#m#s, any number of definitions can be ommited, but the remaining definitions must be in order (so #d#m is still a valid definition, but #m#d is not); ranges: s,m: 0 to 59, h: 0 to 23, d: 0 t o 6, w is unlimited and the first definition is also always unlimited (i.e. for #d#h#m d will be unlimited)

Notice! For variable HDD_KEEP_DUPLICATES_HOURS only h,d and w time units are accepted and a value without a time unit is treated as hours; fractions are rounded to full hours.

Examples:

1.5h is the same as 1h30m, is the same as 90m, is the same as 5400s, is the same as 5400

2.5d is the same as 2d12h, is the same as 60h; 1d36h is not a valid time period (h is not the first definition, so it is bound by range 0 to 23)

1.03m is the same as 62s (61.8 seconds will be rounded up to 62)

Copyright (C) 2025 Jakub Kruszona-Zawadzki, Saglabs SA

This file is part of MooseFS.

MooseFS 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 2 (only).

MooseFS 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 MooseFS; if not, write to the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02111-1301, USA or visit http://www.gnu.org/licenses/gpl-2.0.html

mfschunkserver(8), mfshdd.cfg(5)