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GLOBALIOLIMITS.CFG(5) | GLOBALIOLIMITS.CFG(5) |
NAME¶
globaliolimits.cfg - global I/O limiting configurationDESCRIPTION¶
The file globaliolimits.cfg contains configuration of the global I/O limiter.SYNTAX¶
Syntax is: option value Lines starting with # character are ignored.OPTIONS¶
Configuration options: subsystem <subsystem>The cgroups subsystem by which clients are classified. If
left unspecified, all clients are considered unclassified (see
below).
limit unclassified <throughput in KiB/s>
This is a special entry for clients that don’t
match any group specified in configuration file or for all clients if
subsystem is unspecified. If this entry is unspecified and subsystem is
unspecified as well, I/O limiting is disabled entirely. If this entry is
unspecified but subsystem is specified, unclassified clients are not allowed
to perform I/O.
limit <group> <throughput in KiB/s>
Set limit for clients belonging to the cgroups group
<group>. In LizardFS, subgroups of <group>
constitute independent groups; they are not allowed to use
<group>'s bandwidth reservation and they don’t count
against <group>'s usage.
EXAMPLES¶
# empty file
limit unclassified 1024
subsystem blkio limit /a 1024
subsystem blkio limit unclassified 256 limit /a 1024 limit /b/a 2048
TUNING NOTES¶
Global I/O limiting is managed by the master server. Mount instances reserve bandwidth allocations from master when they want to perform I/O to chunkservers. To avoid overloading the master under heavy traffic, mounts try to predict their future usage and reserve at once all the bandwidth they will for the next renegotiation period (see mfsmaster.cfg(5)). Such reservation are wasted if the traffic at given mount instance suddenly drops. The ratio of bandwidth being wasted due to this phenomenon shouldn’t exceed fsp/b, where:f is the frequency of sudden traffic drops in the whole installation (in 1/s) s is the average size of such drop (in KiB/s) p is the renegotiation period (in s) b is the bandwidth limit (in KiB/s)
COPYRIGHT¶
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)10/27/2016 |