diff options
| -rw-r--r-- | Documentation/btrfs-mount.asciidoc | 58 |
1 files changed, 48 insertions, 10 deletions
diff --git a/Documentation/btrfs-mount.asciidoc b/Documentation/btrfs-mount.asciidoc index 8cf7a0bc..39215a8e 100644 --- a/Documentation/btrfs-mount.asciidoc +++ b/Documentation/btrfs-mount.asciidoc @@ -20,12 +20,17 @@ MOUNT OPTIONS 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). + + @@ -44,19 +49,25 @@ MOUNT OPTIONS 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. @@ -67,6 +78,8 @@ MOUNT OPTIONS 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. @@ -76,14 +89,18 @@ MOUNT OPTIONS 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 @@ -92,10 +109,13 @@ MOUNT OPTIONS 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 @@ -106,48 +126,64 @@ MOUNT OPTIONS 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 @@ -166,7 +202,8 @@ MOUNT 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. @@ -177,6 +214,7 @@ MOUNT OPTIONS 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 |