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

mds cache memory limit

Description

The memory limit the MDS should enforce for its cache. Administrators should use this instead of mds cache size.

Type

64-bit Integer Unsigned

Default

1073741824

mds cache reservation

Description

The cache reservation (memory or inodes) for the MDS cache to maintain. Once the MDS begins dipping into its reservation, it will recall client state until its cache size shrinks to restore the reservation.

Type

Float

Default

0.05

mds cache size

Description

The number of inodes to cache. A value of 0 indicates an unlimited number. It is recommended to use mds_cache_memory_limit to limit the amount of memory the MDS cache uses.

Type

32-bit Integer

Default

0

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. Note, this controls how long failed MDS daemons will stay in the OSDMap blacklist. It has no effect on how long something is blacklisted when the administrator blacklists it manually. For example, ceph osd blacklist add will still use the default blacklist time.

Type

Float

Default

24.0*60.0

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 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 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 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 interval

Description

The frequency (in seconds) of workload exchanges between MDSs.

Type

32-bit Integer

Default

10

mds bal fragment interval

Description

The delay (in seconds) between a fragment being eligible for split or merge and executing the fragmentation change.

Type

32-bit Integer

Default

5

mds bal fragment fast factor

Description

The ratio by which frags may exceed the split size before a split is executed immediately (skipping the fragment interval)

Type

Float

Default

1.5

mds bal fragment size max

Description

The maximum size of a fragment before any new entries are rejected with ENOSPC.

Type

32-bit Integer

Default

100000

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.

  • 0 = Hybrid.

  • 1 = Request rate and latency.

  • 2 = 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

false

mds wipe ino prealloc

Description

Ceph will delete ino preallocation metadata on startup (for testing only).

Type

Boolean

Default

false

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

mds min caps per client

Description

Set the minimum number of capabilities a client may hold.

Type

Integer

Default

100

mds max ratio caps per client

Description

Set the maximum ratio of current caps that may be recalled during MDS cache pressure.

Type

Float

Default

0.8