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

v.65 版后已移除.

filestore_flusher_max_fds

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

v.65 版后已移除.

filestore_sync_flush

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

v.65 版后已移除.

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