bionic (5) mfsgoals.cfg.5.gz

Provided by: lizardfs-master_3.12.0+dfsg-1_amd64 bug

NAME

       mfsgoals.cfg - replication goals configuration file

DESCRIPTION

       The file mfsgoals.cfg contains definitions of the replication goals.

SYNTAX

       Syntax is:

       id name : $type { label ... } id name : label ...

       The # character starts comments.

DETAILS

       There are 40 replication goals, with ids between 1 and 40, inclusive. Each file stored on the filesystem
       refers to some goal id and is replicated according to the goal currently associated with this id.

       By default, goal 1 means one copy on any chunkserver, goal 2 means two copies on any two chunkservers and
       so on, until 5 - which is the maximal default number of copies. The purpose of mfsgoals.cfg is to
       override this behavior, when desired. The file is a list of goal definitions, each consisting of id, name
       and a list of labels. The maximal length of this list is 40 labels.

       id indicates the goal id to be redefined. If some files are already assigned this goal id, their
       effective goal will change.

       name is a human readable name used by the user interface tools (mfssetgoal(1), mfsgetgoal(1)). name can
       consist of up to 32 alphanumeric characters: a-z, A-Z, 0-9, _.

       type specifies goal type - currently supported types are:

       •   std - for each file using this goal and for each label, the system will try to maintain a copy of the
           file on some chunkserver with this label.

       •   xorN - for each file using this goal, the system will split the file into N+1 parts (N ordinary + 1
           parity). For reading, any N of the parts are necessary. If labels are specified, parts will be kept
           on chunkservers with these labels. Otherwise, default wildcard labels will be used. N can be in range
           from 2 to 9.

       •   ec(K,M) - for each file using this goal, the system will split the file into K + M parts (K data
           parts and M parity). For reading, any K of the parts are necessary. If labels are specified, parts
           will be kept on chunkservers with these labels. Otherwise, default wildcard labels will be used. K
           can be in range from 2 to 32 and M from 1 to 32. If the type is unspecified is is assumed to be std.

       The list of labels is a list of chunkserver labels as defined in mfschunkserver.cfg(5). label can consist
       of up to 32 alphanumeric characters: a-z, A-Z, 0-9, _.

       One label may occur multiple times - in such case the system will create one copy per each occurrence.
       The special label _ means "a copy on any chunkserver".

       Note that changing the definition of a goal in mfsgoals.cfg affects all files which currently use given
       goal id.

EXAMPLES

       Some example goal definitions:

       3 3 : _ _ _ # one of the default goals (three copies anywhere)

       8 not_important_file : _ # only one copy

       11 important_file : _ _

       12 local_copy_on_mars : mars _ # at least one copy in the Martian datacenter

       13 cached_on_ssd : ssd _

       14 very_important_file : _ _ _ _

       15 default_xor3 : $xor3

       16 fast_read : $xor2 { ssd ssd hdd }

       17 xor5 : $xor5 { hdd } # at least one part on hdd

       18 first_ec : $ec(3,1)

       19 ec32_ssd : $ec(3,2) { ssd ssd ssd ssd ssd } # all parts on ssd

       20 ec53_mixed : $ec(5,3) { hdd ssd hdd _ _ _ _ _ } # two parts on hdd and one part on ssd

SNAPSHOT FILES

       Snapshot shares data with the original file until the file receives modification and diverges from the
       snapshotted version. If some snapshot has different goal than its original file, any shared data are
       stored according to the goal with higher id of the two.

       Copyright 2008-2009 Gemius SA, 2013-2015 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.cfg(5)

                                                   02/11/2018                                    MFSGOALS.CFG(5)