Default is 1MB.
*autodefrag*::
+*noautodefrag*::
+ (since: 3.0, default: off) +
Disable/enable auto defragmentation.
Auto defragmentation detects small random writes into files and queue
them up for the defrag process. Works best for small files;
Not well suited for large database workloads.
-*check_int*|*check_int_data*|*check_int_print_mask='value'*::
+*check_int*::
+*check_int_data*::
+*check_int_print_mask='value'*::
+ (since: 3.0, default: off) +
These debugging options control the behavior of the integrity checking
module (the BTRFS_FS_CHECK_INTEGRITY config option required). +
+
for more info.
*commit='seconds'*::
- Set the interval of periodic commit, 30 seconds by default. Higher
+ (since: 3.12, default: 30) +
+ Set the interval of periodic commit. Higher
values defer data being synced to permanent storage with obvious
consequences when the system crashes. The upper bound is not forced,
but a warning is printed if it's more than 300 seconds (5 minutes).
-*compress*|*compress='type'*|*compress-force*|*compress-force='type'*::
- Control BTRFS file data compression. Type may be specified as "zlib"
- "lzo" or "no" (for no compression, used for remounting). If no type
- is specified, zlib is used. If compress-force is specified,
+*compress*::
+*compress='type'*::
+*compress-force*::
+*compress-force='type'*::
+ (default: off) +
+ Control BTRFS file data compression. Type may be specified as 'zlib',
+ 'lzo' or 'no' (for no compression, used for remounting). If no type
+ is specified, 'zlib' is used. If compress-force is specified,
all files will be compressed, whether or not they compress well.
- If compression is enabled, nodatacow and nodatasum are disabled.
+ NOTE: If compression is enabled, 'nodatacow' and 'nodatasum' are disabled.
*degraded*::
+ (default: off) +
Allow mounts to continue with missing devices. A read-write mount may
fail with too many devices missing, for example if a stripe member
is completely missing.
setup as root. May be specified multiple times for multiple devices.
*discard*::
+*nodiscard*::
+ (default: off) +
Disable/enable discard mount option.
Discard issues frequent commands to let the block device reclaim space
freed by the filesystem.
initiate batch trims from userspace).
*enospc_debug*::
+ (default: off) +
Disable/enable debugging option to be more verbose in some ENOSPC conditions.
*fatal_errors='action'*::
+ (since: 3.4, default: bug) +
Action to take when encountering a fatal error. +
- "bug" - BUG() on a fatal error. This is the default. +
+ "bug" - BUG() on a fatal error. +
"panic" - panic() on a fatal error.
*flushoncommit*::
+*noflushoncommit*::
+ (default: on) +
The `flushoncommit` mount option forces any data dirtied by a write in a
prior transaction to commit as part of the current commit. This makes
the committed state a fully consistent view of the file system from the
created.
*inode_cache*::
+*noinode_cache*::
+ (since: 3.0, default: off) +
Enable free inode number caching. Defaults to off due to an overflow
problem when the free space crcs don't fit inside a single page.
*max_inline='bytes'*::
+ (default: min(8192, page size) )
Specify the maximum amount of space, in bytes, that can be inlined in
a metadata B-tree leaf. The value is specified in bytes, optionally
with a K, M, or G suffix, case insensitive. In practice, this value
Specify that 1 metadata chunk should be allocated after every
'value' data chunks. Off by default.
+*acl*::
*noacl*::
+ (default: on) +
Enable/disable support for Posix Access Control Lists (ACLs). See the
`acl`(5) manual page for more information about ACLs.
+*barrier*::
*nobarrier*::
+ (default: on) +
ensure that certain IOs make it through the device cache and are on
persistent storage. If disabled on a device with a volatile
(non-battery-backed) write-back cache, nobarrier option will lead to
filesystem corruption on a system crash or power loss.
+*datacow*::
*nodatacow*::
+ (default: on) +
Enable/disable data copy-on-write for newly created files.
Nodatacow implies nodatasum, and disables all compression.
+*datasum*::
*nodatasum*::
+ (default: on) +
Enable/disable data checksumming for newly created files.
Datasum implies datacow.
+*treelog*::
*notreelog*::
+ (default: on) +
Enable/disable the tree logging used for fsync and O_SYNC writes.
*recovery*::
+ (since: 3.2, default: off) +
Enable autorecovery attempts if a bad tree root is found at mount time.
Currently this scans a list of several previous tree roots and tries to
use the first readable.
*rescan_uuid_tree*::
+ (since: 3.12, default: off) +
Force check and rebuild procedure of the UUID tree. This should not
normally be needed.
*skip_balance*::
+ (since: 3.3, default: off) +
Skip automatic resume of interrupted balance operation after mount.
May be resumed with "btrfs balance resume."
*nospace_cache*::
+ (since: 3.2) +
Disable freespace cache loading without clearing the cache.
*clear_cache*::
Force clearing and rebuilding of the disk space cache if something
has gone wrong.
-*ssd*|*nossd*|*ssd_spread*::
+*ssd*::
+*nossd*::
+*ssd_spread*::
Options to control ssd allocation schemes. By default, BTRFS will
enable or disable ssd allocation heuristics depending on whether a
rotational or nonrotational disk is in use. The ssd and nossd options
filesystem.
You can use "btrfs subvolume list" to see subvolume ID numbers.
-*subvolrootid='objectid' (deprecated)*::
+*subvolrootid='objectid'*::
+ (deprecated) +
Mount subvolume specified by 'objectid' rather than the root subvolume.
This allows mounting of subvolumes which are not in the root of the mounted
filesystem.
to the number of CPUs + 2, or 8, whichever is smaller.
*user_subvol_rm_allowed*::
+ (default: off) +
Allow subvolumes to be deleted by a non-root user. Use with caution.
FILE ATTRIBUTES
projects / platform / upstream / btrfs-progs.git / commitdiff