ceph/doc/config-cluster/filestore-config-ref.rst

============================
 Filestore Config Reference
============================



``filestore debug omap check``

:Description: Debugging check on synchronization. Expensive. For debugging only.
:Type: Boolean
:Required: No
:Default: ``0``


Extended Attributes
===================

Extended Attributes (XATTRs) are an imporant aspect in your configuration. 
Some file systems have limits on the number of bytes stored in XATTRS. 
Additionally, in some cases, the filesystem may not be as fast as an alternative
method of storing XATTRs. The following settings may help improve performance
by using a method of storing XATTRs that is extrinsic to the underlying filesystem.


``filestore xattr use omap``

:Description: Use object map for XATTRS. Set to ``true`` for ``ext4`` file systems. 
:Type: Boolean
:Required: No
:Default: ``false``


``filestore max inline xattr size``

:Description: The maximimum size of an XATTR stored in the filesystem (i.e., XFS, btrfs, ext4, etc.) per object. Should not be larger than the filesytem can handle.
:Type: Unsigned 32-bit Integer
:Required: No
:Default: ``512``


``filestore max inline xattrs``

:Description: The maximum number of XATTRs stored in the fileystem per object.
:Type: 32-bit Integer
:Required: No
:Default: ``2``


Synchronization Intervals
=========================

Periodically, the filestore needs to quiesce writes and synchronize the filesystem,
which creates a consistent commit point. It can then free journal entries up to
the commit point. Synchronizing more frequently tends to reduce the time required 
perform synchronization, and reduces the amount of data that needs to remain in the 
journal. Less frequent synchronization allows the backing filesystem to coalesce 
small writes and metadata updates more optimally--potentially resulting in more
efficient synchronization.


``filestore max sync interval``

:Description: The maximum interval in seconds for synchronizing the filestore.
:Type: Double
:Required: No
:Default: ``5``


``filestore min sync interval``

:Description: The minimum interval in seconds for synchronizing the filestore.
:Type: Double
:Required: No
:Default: ``.01``


Flusher
=======

The filestore flusher forces data from large writes to be written out using
``sync file range`` before the sync in order to (hopefully) reduce the cost of
the eventual sync. In practice, disabling 'filestore flusher' seems to improve
performance in some cases.


``filestore flusher``

:Description: Enables the filestore flusher.
:Type: Boolean
:Required: No
:Default: ``false``


``filestore flusher max fds``

:Description: Sets the maximum number of file descriptors for the flusher.
:Type: Integer
:Required: No
:Default: ``512``

``filestore sync flush``

:Description: Enables the synchronization flusher. 
:Type: Boolean
:Required: No
:Default: ``false``


``filestore fsync flushes journal data``

:Description: Flush journal data during filesystem synchronization.
:Type: Boolean
:Required: No
:Default: ``false``


Queue
=====

The following settings provide limits on the size of filestore queue.

``filestore queue max ops``

:Description: Defines the maximum number of in progress operations the file store accepts before blocking on queuing new operations. 
:Type: Integer
:Required: No. Minimal impact on performance.
:Default: ``500``


``filestore queue max bytes``

:Description: The maximum number of bytes for an operation. 
:Type: Integer
:Required: No
:Default: ``100 << 20``


``filestore queue committing max ops``

:Description: The maximum number of operations the filestore can commit. 
:Type: Integer
:Required: No
:Default: ``500``


``filestore queue committing max bytes``

:Description: The maximum number of bytes the filestore can commit.
:Type: Integer
:Required: No
:Default: ``100 << 20``



Timeouts
========


``filestore op threads``

:Description: The number of filesystem operation threads that execute in parallel. 
:Type: Integer
:Required: No
:Default: ``2``


``filestore op thread timeout``

:Description: The timeout for a filesystem operation thread (in seconds).
:Type: Integer
:Required: No
:Default: ``60``


``filestore op thread suicide timeout``

:Description: The timeout for a commit operation before cancelling the commit (in seconds). 
:Type: Integer
:Required: No
:Default: ``180``


B-Tree Filesystem
=================


``filestore btrfs snap``

:Description: Enable snapshots for a ``btrfs`` filestore.
:Type: Boolean
:Required: No. Only used for ``btrfs``.
:Default: ``true``


``filestore btrfs clone range``

:Description: Enable cloning ranges for a ``btrfs`` filestore.
:Type: Boolean
:Required: No. Only used for ``btrfs``.
:Default: ``true``

Journal
=======


``filestore journal parallel``

:Description: 
:Type: Boolean
:Required: No
:Default: ``false``


``filestore journal writeahead``

:Description:
:Type: Boolean
:Required: No
:Default: ``false``


``filestore journal trailing``

:Description:
:Type: Boolean
:Required: No
:Default: ``false``


Misc
====


``filestore merge threshold``

:Description: 
:Type: Integer
:Required: No
:Default: ``10``


``filestore split multiple``

:Description: 
:Type: Integer
:Required: No
:Default: ``2``


``filestore update to``

:Description: 
:Type: Integer
:Required: No
:Default: ``1000``


``filestore blackhole``

:Description: Drop any new transactions on the floor.
:Type: Boolean
:Required: No
:Default: ``false``


``filestore dump file``

:Description: File onto which store transaction dumps?
:Type: Boolean
:Required: No
:Default: ``false``


``filestore kill at``

:Description: inject a failure at the n'th opportunity
:Type: String
:Required: No
:Default: ``false``


``filestore fail eio``

:Description: Fail/Crash on eio.
:Type: Boolean
:Required: No
:Default: ``true``