GLOBALIOLIMITS.CFG(5) GLOBALIOLIMITS.CFG(5) NAME globaliolimits.cfg - global I/O limiting configuration DESCRIPTION The file globaliolimits.cfg contains configuration of the global I/O lim- iter. 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 unspeci- fied, 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 speci- fied in configuration file or for all clients if subsystem is unspeci- fied. 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 I/O limiting is disabled, no limits are enforced. limit unclassified 1024 All clients are unclassified and share 1MiB/s of bandwidth. subsystem blkio limit /a 1024 Clients in the blkio /a group are limited to 1MiB/s, no other clients can perform any I/O. subsystem blkio limit unclassified 256 limit /a 1024 limit /b/a 2048 The blkio group /a is allowed to transfer 1MiB/s, while /b/a gets 2MiB/s. Clients from other groups (e.g. /b, /z, /a/a, /b/z) are considered unclas- sified and share 256KiB/s of bandwidth. TUNING NOTES Global I/O limiting is managed by the master server. Mount instances re- serve 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) This applies to each group separately, because groups reserve their band- width independently from each other. 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 Soft- ware 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 de- tails. 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) 08/30/2026 GLOBALIOLIMITS.CFG(5)
NAME | DESCRIPTION | SYNTAX | OPTIONS | EXAMPLES | TUNING NOTES | COPYRIGHT | SEE ALSO
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