Filestore Config Reference
Note
Since the Luminous release of Ceph, Filestore has not been Ceph’s default storage back end. Since the Luminous release of Ceph, BlueStore has been Ceph’s default storage back end. However, Filestore OSDs are still supported up to Quincy. Filestore OSDs are not supported in Reef. See OSD Back Ends. See BlueStore Migration for instructions explaining how to replace an existing Filestore back end with a BlueStore back end.
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. However, Certain disadvantages can occur when the underlying file system is used for the storage of XATTRs: some file systems have limits on the number of bytes that can be stored in XATTRs, and your file system might in some cases therefore run slower than would an alternative method of storing XATTRs. For this reason, a method of storing XATTRs extrinsic to the underlying file system might improve performance. To implement such an extrinsic method, refer to the following settings.
If the underlying file system has no size limit, then Ceph XATTRs are stored as
inline xattr, using the XATTRs provided by the file system. But if there is
a size limit (for example, ext4 imposes a limit of 4 KB total), then some Ceph
XATTRs will be stored in a key/value database when the limit is reached. More
precisely, this begins to occur when either the
filestore_max_inline_xattr_size or filestore_max_inline_xattrs
threshold is reached.
filestore_max_inline_xattr_size
- Description:
Defines the maximum size per object of an XATTR that can be stored in the file system (for example, XFS, Btrfs, ext4). The specified size should not be larger than the file system can handle. Using the default value of 0 instructs Filestore to use the value specific to the file system.
- Type:
Unsigned 32-bit Integer
- Required:
No
- Default:
0
filestore_max_inline_xattr_size_xfs
- Description:
Defines the maximum size of an XATTR that can be stored in the XFS file system. This setting is used only if
filestore_max_inline_xattr_size== 0.- Type:
Unsigned 32-bit Integer
- Required:
No
- Default:
65536
filestore_max_inline_xattr_size_btrfs
- Description:
Defines the maximum size of an XATTR that can be stored in the Btrfs file system. This setting is used only if
filestore_max_inline_xattr_size== 0.- Type:
Unsigned 32-bit Integer
- Required:
No
- Default:
2048
filestore_max_inline_xattr_size_other
- Description:
Defines the maximum size of an XATTR that can be stored in other file systems. This setting is used only if
filestore_max_inline_xattr_size== 0.- Type:
Unsigned 32-bit Integer
- Required:
No
- Default:
512
filestore_max_inline_xattrs
- Description:
Defines the maximum number of XATTRs per object that can be stored in the file system. Using the default value of 0 instructs Filestore to use the value specific to the file system.
- Type:
32-bit Integer
- Required:
No
- Default:
0
filestore_max_inline_xattrs_xfs
- Description:
Defines the maximum number of XATTRs per object that can be stored in the XFS file system. This setting is used only if
filestore_max_inline_xattrs== 0.- Type:
32-bit Integer
- Required:
No
- Default:
10
filestore_max_inline_xattrs_btrfs
- Description:
Defines the maximum number of XATTRs per object that can be stored in the Btrfs file system. This setting is used only if
filestore_max_inline_xattrs== 0.- Type:
32-bit Integer
- Required:
No
- Default:
10
filestore_max_inline_xattrs_other
- Description:
Defines the maximum number of XATTRs per object that can be stored in other file systems. This setting is used only if
filestore_max_inline_xattrs== 0.- Type:
32-bit Integer
- Required:
No
- Default:
2
Synchronization Intervals
Filestore must periodically quiesce writes and synchronize the file system. Each synchronization creates a consistent commit point. When the commit point is created, Filestore is able to free all journal entries up to that point. More-frequent synchronization tends to reduce both synchronization time and 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, potentially increasing synchronization efficiency but also potentially increasing tail latency.
filestore_max_sync_interval
- Description:
Defines the maximum interval (in seconds) for synchronizing Filestore.
- Type:
Double
- Required:
No
- Default:
5
filestore_min_sync_interval
- Description:
Defines 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 prior to the synchronization.
Ideally, this action reduces the cost of the eventual synchronization. In practice, however, disabling
‘filestore_flusher’ seems in some cases to improve performance.
filestore_flusher
- Description:
Enables the Filestore flusher.
- Type:
Boolean
- Required:
No
- Default:
false
Deprecated since version v.65.
filestore_flusher_max_fds
- Description:
Defines 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:
Flushes journal data during file-system synchronization.
- Type:
Boolean
- Required:
No
- Default:
false
Queue
The following settings define limits on the size of the Filestore queue:
filestore_queue_max_ops
- Description:
Defines the maximum number of in-progress operations that Filestore accepts before it blocks the queueing of any new operations.
- Type:
Integer
- Required:
No. Minimal impact on performance.
- Default:
50
filestore_queue_max_bytes
- Description:
Defines the maximum number of bytes permitted per operation.
- Type:
Integer
- Required:
No
- Default:
100 << 20
Timeouts
filestore_op_threads
- Description:
Defines the number of file-system operation threads that execute in parallel.
- Type:
Integer
- Required:
No
- Default:
2
filestore_op_thread_timeout
- Description:
Defines the timeout (in seconds) for a file-system operation thread.
- Type:
Integer
- Required:
No
- Default:
60
filestore_op_thread_suicide_timeout
- Description:
Defines the timeout (in seconds) for a commit operation before the commit is cancelled.
- Type:
Integer
- Required:
No
- Default:
180
B-Tree Filesystem
filestore_btrfs_snap
- Description:
Enables snapshots for a
btrfsFilestore.- Type:
Boolean
- Required:
No. Used only for
btrfs.- Default:
true
filestore_btrfs_clone_range
- Description:
Enables cloning ranges for a
btrfsFilestore.- Type:
Boolean
- Required:
No. Used only 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 write-ahead 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:
Defines the minimum number of files permitted in a subdirectory before the subdirectory is merged into its parent directory. NOTE: A negative value means that subdirectory merging is disabled.
- Type:
Integer
- Required:
No
- Default:
-10
filestore_split_multiple
- Description:
(filestore_split_multiple * abs(filestore_merge_threshold) + (rand() % filestore_split_rand_factor)) * 16is the maximum number of files permitted in a subdirectory before the subdirectory is split 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 the same time. For details, see
filestore_split_multiple. To change this setting for an existing OSD, it is necessary to take the OSD offline before running theceph-objectstore-tool apply-layout-settingscommand.- Type:
Unsigned 32-bit Integer
- Required:
No
- Default:
20
filestore_update_to
- Description:
Limits automatic upgrades to a specified version of Filestore. Useful in cases in which you want to avoid upgrading to a specific version.
- Type:
Integer
- Required:
No
- Default:
1000
filestore_blackhole
- Description:
Drops any new transactions on the floor, similar to redirecting to NULL.
- Type:
Boolean
- Required:
No
- Default:
false
filestore_dump_file
- Description:
Defines the file that transaction dumps are stored on.
- Type:
Boolean
- Required:
No
- Default:
false
filestore_kill_at
- Description:
Injects a failure at the nth opportunity.
- Type:
String
- Required:
No
- Default:
false
filestore_fail_eio
- Description:
Fail/Crash on EIO.
- Type:
Boolean
- Required:
No
- Default:
true
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