MDS Config Reference

mon force standby active

Description:If true monitors force standby-replay to be active. Set under [mon] or [global]. Type:Boolean Default:true

max mds

Description:The number of active MDS daemons during cluster creation. Set under [mon] or [global]. Type:32-bit Integer Default:1

mds max file size

Description:The maximum allowed file size to set when creating a new file system. Type:64-bit Integer Unsigned Default:1ULL << 40

mds cache size

Description:The number of inodes to cache. Type:32-bit Integer Default:100000

mds cache mid

Description:The insertion point for new items in the cache LRU (from the top). Type:Float Default:0.7

mds dir commit ratio

Description:The fraction of directory that is dirty before Ceph commits using a full update (instead of partial update). Type:Float Default:0.5

mds dir max commit size

Description:The maximum size of a directory update before Ceph breaks it into smaller transactions) (MB). Type:32-bit Integer Default:90

mds decay halflife

Description:The half-life of MDS cache temperature. Type:Float Default:5

mds beacon interval

Description:The frequency (in seconds) of beacon messages sent to the monitor. Type:Float Default:4

mds beacon grace

Description:The interval without beacons before Ceph declares an MDS laggy (and possibly replace it). Type:Float Default:15

mds blacklist interval

Description:The blacklist duration for failed MDSs in the OSD map. Type:Float Default:24.0*60.0

mds session timeout

Description:The interval (in seconds) of client inactivity before Ceph times out capabilities and leases. Type:Float Default:60

mds session autoclose

Description:The interval (in seconds) before Ceph closes a laggy client’s session. Type:Float Default:300

mds reconnect timeout

Description:The interval (in seconds) to wait for clients to reconnect during MDS restart. Type:Float Default:45

mds tick interval

Description:How frequently the MDS performs internal periodic tasks. Type:Float Default:5

mds dirstat min interval

Description:The minimum interval (in seconds) to try to avoid propagating recursive stats up the tree. Type:Float Default:1

mds scatter nudge interval

Description:How quickly dirstat changes propagate up. Type:Float Default:5

mds client prealloc inos

Description:The number of inode numbers to preallocate per client session. Type:32-bit Integer Default:1000

mds early reply

Description:Determines whether the MDS should allow clients to see request results before they commit to the journal. Type:Boolean Default:true

mds use tmap

Description:Use trivialmap for directory updates. Type:Boolean Default:true

mds default dir hash

Description:The function to use for hashing files across directory fragments. Type:32-bit Integer Default:2 (i.e., rjenkins)

mds log

Description:Set to true if the MDS should journal metadata updates (disabled for benchmarking only). Type:Boolean Default:true

mds log skip corrupt events

Description:Determines whether the MDS should try to skip corrupt journal events during journal replay. Type:Boolean Default:false

mds log max events

Description:The maximum events in the journal before we initiate trimming. Set to -1 to disable limits. Type:32-bit Integer Default:-1

mds log max segments

Description:The maximum number of segments (objects) in the journal before we initiate trimming. Set to -1 to disable limits. Type:32-bit Integer Default:30

mds log max expiring

Description:The maximum number of segments to expire in parallels Type:32-bit Integer Default:20

mds log eopen size

Description:The maximum number of inodes in an EOpen event. Type:32-bit Integer Default:100

mds bal sample interval

Description:Determines how frequently to sample directory temperature (for fragmentation decisions). Type:Float Default:3

mds bal replicate threshold

Description:The maximum temperature before Ceph attempts to replicate metadata to other nodes. Type:Float Default:8000

mds bal unreplicate threshold

Description:The minimum temperature before Ceph stops replicating metadata to other nodes. Type:Float Default:0

mds bal frag

Description:Determines whether the MDS will fragment directories. Type:Boolean Default:false

mds bal split size

Description:The maximum directory size before the MDS will split a directory fragment into smaller bits. Type:32-bit Integer Default:10000

mds bal split rd

Description:The maximum directory read temperature before Ceph splits a directory fragment. Type:Float Default:25000

mds bal split wr

Description:The maximum directory write temperature before Ceph splits a directory fragment. Type:Float Default:10000

mds bal split bits

Description:The number of bits by which to split a directory fragment. Type:32-bit Integer Default:3

mds bal merge size

Description:The minimum directory size before Ceph tries to merge adjacent directory fragments. Type:32-bit Integer Default:50

mds bal merge rd

Description:The minimum read temperature before Ceph merges adjacent directory fragments. Type:Float Default:1000

mds bal merge wr

Description:The minimum write temperature before Ceph merges adjacent directory fragments. Type:Float Default:1000

mds bal interval

Description:The frequency (in seconds) of workload exchanges between MDSs. Type:32-bit Integer Default:10

mds bal fragment interval

Description:The frequency (in seconds) of adjusting directory fragmentation. Type:32-bit Integer Default:5

mds bal idle threshold

Description:The minimum temperature before Ceph migrates a subtree back to its parent. Type:Float Default:0

mds bal max

Description:The number of iterations to run balancer before Ceph stops. (used for testing purposes only) Type:32-bit Integer Default:-1

mds bal max until

Description:The number of seconds to run balancer before Ceph stops. (used for testing purposes only) Type:32-bit Integer Default:-1

mds bal mode

Description:

The method for calculating MDS load.

• 1 = Hybrid.
• 2 = Request rate and latency.
• 3 = CPU load.

Type:

32-bit Integer

Default:

0

mds bal min rebalance

Description:The minimum subtree temperature before Ceph migrates. Type:Float Default:0.1

mds bal min start

Description:The minimum subtree temperature before Ceph searches a subtree. Type:Float Default:0.2

mds bal need min

Description:The minimum fraction of target subtree size to accept. Type:Float Default:0.8

mds bal need max

Description:The maximum fraction of target subtree size to accept. Type:Float Default:1.2

mds bal midchunk

Description:Ceph will migrate any subtree that is larger than this fraction of the target subtree size. Type:Float Default:0.3

mds bal minchunk

Description:Ceph will ignore any subtree that is smaller than this fraction of the target subtree size. Type:Float Default:0.001

mds bal target removal min

Description:The minimum number of balancer iterations before Ceph removes an old MDS target from the MDS map. Type:32-bit Integer Default:5

mds bal target removal max

Description:The maximum number of balancer iteration before Ceph removes an old MDS target from the MDS map. Type:32-bit Integer Default:10

mds replay interval

Description:The journal poll interval when in standby-replay mode. (“hot standby”) Type:Float Default:1

mds shutdown check

Description:The interval for polling the cache during MDS shutdown. Type:32-bit Integer Default:0

mds thrash exports

Description:Ceph will randomly export subtrees between nodes (testing only). Type:32-bit Integer Default:0

mds thrash fragments

Description:Ceph will randomly fragment or merge directories. Type:32-bit Integer Default:0

mds dump cache on map

Description:Ceph will dump the MDS cache contents to a file on each MDSMap. Type:Boolean Default:false

mds dump cache after rejoin

Description:Ceph will dump MDS cache contents to a file after rejoining the cache (during recovery). Type:Boolean Default:false

mds verify scatter

Description:Ceph will assert that various scatter/gather invariants are true (developers only). Type:Boolean Default:false

mds debug scatterstat

Description:Ceph will assert that various recursive stat invariants are true (for developers only). Type:Boolean Default:false

mds debug frag

Description:Ceph will verify directory fragmentation invariants when convenient (developers only). Type:Boolean Default:false

mds debug auth pins

Description:The debug auth pin invariants (for developers only). Type:Boolean Default:false

mds debug subtrees

Description:The debug subtree invariants (for developers only). Type:Boolean Default:false

mds kill mdstable at

Description:Ceph will inject MDS failure in MDSTable code (for developers only). Type:32-bit Integer Default:0

mds kill export at

Description:Ceph will inject MDS failure in the subtree export code (for developers only). Type:32-bit Integer Default:0

mds kill import at

Description:Ceph will inject MDS failure in the subtree import code (for developers only). Type:32-bit Integer Default:0

mds kill link at

Description:Ceph will inject MDS failure in hard link code (for developers only). Type:32-bit Integer Default:0

mds kill rename at

Description:Ceph will inject MDS failure in the rename code (for developers only). Type:32-bit Integer Default:0

mds wipe sessions

Description:Ceph will delete all client sessions on startup (for testing only). Type:Boolean Default:0

mds wipe ino prealloc

Description:Ceph will delete ino preallocation metadata on startup (for testing only). Type:Boolean Default:0

mds skip ino

Description:The number of inode numbers to skip on startup (for testing only). Type:32-bit Integer Default:0

mds standby for name

Description:An MDS daemon will standby for another MDS daemon of the name specified in this setting. Type:String Default:N/A

mds standby for rank

Description:An MDS daemon will standby for an MDS daemon of this rank. Type:32-bit Integer Default:-1

mds standby replay

Description:Determines whether a ceph-mds daemon should poll and replay the log of an active MDS (hot standby). Type:Boolean Default:false