Filestore Config Reference

The Filestore back end is no longer the default when creating new OSDs, though Filestore OSDs are still supported.

filestore debug omap check

Description

Debugging check on synchronization. Expensive. For debugging only.

Type

Boolean

Required

No

Default

false

Extended Attributes

Extended Attributes (XATTRs) are important for Filestore OSDs. Some file systems have limits on the number of bytes that can be stored in XATTRs. Additionally, in some cases, the file system 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 file system.

Ceph XATTRs are stored as inline xattr, using the XATTRs provided by the underlying file system, if it does not impose a size limit. If there is a size limit (4KB total on ext4, for instance), some Ceph XATTRs will be stored in a key/value database when either the filestore_max_inline_xattr_size or filestore_max_inline_xattrs threshold is reached.

filestore_max_inline_xattr_size

Description

The maximum size of an XATTR stored in the file system (i.e., XFS, Btrfs, EXT4, etc.) per object. Should not be larger than the file system can handle. Default value of 0 means to use the value specific to the underlying file system.

Type

Unsigned 32-bit Integer

Required

No

Default

0

filestore_max_inline_xattr_size_xfs

Description

The maximum size of an XATTR stored in the XFS file system. Only used if filestore_max_inline_xattr_size == 0.

Type

Unsigned 32-bit Integer

Required

No

Default

65536

filestore_max_inline_xattr_size_btrfs

Description

The maximum size of an XATTR stored in the Btrfs file system. Only used if filestore_max_inline_xattr_size == 0.

Type

Unsigned 32-bit Integer

Required

No

Default

2048

filestore_max_inline_xattr_size_other

Description

The maximum size of an XATTR stored in other file systems. Only used if filestore_max_inline_xattr_size == 0.

Type

Unsigned 32-bit Integer

Required

No

Default

512

filestore_max_inline_xattrs

Description

The maximum number of XATTRs stored in the file system per object. Default value of 0 means to use the value specific to the underlying file system.

Type

32-bit Integer

Required

No

Default

0

filestore_max_inline_xattrs_xfs

Description

The maximum number of XATTRs stored in the XFS file system per object. Only used if filestore_max_inline_xattrs == 0.

Type

32-bit Integer

Required

No

Default

10

filestore_max_inline_xattrs_btrfs

Description

The maximum number of XATTRs stored in the Btrfs file system per object. Only used if filestore_max_inline_xattrs == 0.

Type

32-bit Integer

Required

No

Default

10

filestore_max_inline_xattrs_other

Description

The maximum number of XATTRs stored in other file systems per object. Only used if filestore_max_inline_xattrs == 0.

Type

32-bit Integer

Required

No

Default

2

Synchronization Intervals

Filestore needs to periodically quiesce writes and synchronize the file system, 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 to perform synchronization, and reduces the amount of data that needs to remain in the journal. Less frequent synchronization allows the backing file system to coalesce small writes and metadata updates more optimally, potentially resulting in more efficient synchronization at the expense of potentially increasing tail latency.

filestore_max_sync_interval

Description

The maximum interval in seconds for synchronizing Filestore.

Type

Double

Required

No

Default

5

filestore_min_sync_interval

Description

The minimum interval in seconds for synchronizing 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

Deprecated since version v.65.

filestore_flusher_max_fds

Description

Sets the maximum number of file descriptors for the flusher.

Type

Integer

Required

No

Default

512

Deprecated since version v.65.

filestore_sync_flush

Description

Enables the synchronization flusher.

Type

Boolean

Required

No

Default

false

Deprecated since version v.65.

filestore_fsync_flushes_journal_data

Description

Flush journal data during file system synchronization.

Type

Boolean

Required

No

Default

false

Queue

The following settings provide limits on the size of the 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

50

filestore_queue_max_bytes

Description

The maximum number of bytes for an operation.

Type

Integer

Required

No

Default

100 << 20

Timeouts

filestore_op_threads

Description

The number of file system operation threads that execute in parallel.

Type

Integer

Required

No

Default

2

filestore_op_thread_timeout

Description

The timeout for a file system 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

Enables parallel journaling, default for Btrfs.

Type

Boolean

Required

No

Default

false

filestore_journal_writeahead

Description

Enables writeahead journaling, default for XFS.

Type

Boolean

Required

No

Default

false

filestore_journal_trailing

Description

Deprecated, never use.

Type

Boolean

Required

No

Default

false

Misc

filestore_merge_threshold

Description

Min number of files in a subdir before merging into parent NOTE: A negative value means to disable subdir merging

Type

Integer

Required

No

Default

-10

filestore_split_multiple

Description

(filestore_split_multiple * abs(filestore_merge_threshold) + (rand() % filestore_split_rand_factor)) * 16 is the maximum number of files in a subdirectory before splitting into child directories.

Type

Integer

Required

No

Default

2

filestore_split_rand_factor

Description

A random factor added to the split threshold to avoid too many (expensive) Filestore splits occurring at once. See filestore_split_multiple for details. This can only be changed offline for an existing OSD, via the ceph-objectstore-tool apply-layout-settings command.

Type

Unsigned 32-bit Integer

Required

No

Default

20

filestore_update_to

Description

Limits Filestore auto upgrade to specified version.

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