======================
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``