diff options
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/btrfs-inspect-internal.asciidoc | 29 | ||||
| -rw-r--r-- | Documentation/btrfs-man5.asciidoc | 15 | ||||
| -rw-r--r-- | Documentation/btrfs-subvolume.asciidoc | 6 | ||||
| -rw-r--r-- | Documentation/mkfs.btrfs.asciidoc | 20 |
4 files changed, 48 insertions, 22 deletions
diff --git a/Documentation/btrfs-inspect-internal.asciidoc b/Documentation/btrfs-inspect-internal.asciidoc index 74f6dea8..44615e76 100644 --- a/Documentation/btrfs-inspect-internal.asciidoc +++ b/Documentation/btrfs-inspect-internal.asciidoc @@ -30,25 +30,36 @@ Besides verifictaion of the filesystem signature, there are no other sanity checks. The superblock checksum status is reported, the device item and filesystem UUIDs are checked and reported. + +NOTE: the meaning of option '-s' has changed in version 4.8 to be consistent +with other tools to specify superblock copy rather the offset. The old way still +works, but prints a warning. Please update your scripts to use '--bytenr' +instead. The option '-i' has been deprecated. ++ `Options` + -f|--full:::: print full superblock information, including the system chunk array and backup roots -a|--all:::: -print information about all present superblock copies (cannot be used together with '-i' option) --i <super_mirror>:::: -specify which mirror to print, valid values are 0, 1 and 2 and the superblock must be present on the device +print information about all present superblock copies (cannot be used together +with '-s' option) +-i <super>:::: +(deprecated since 4.8, same behaviour as '--super') +--bytenr <bytenr>:::: +specify offset to a superblock in a non-standard location at 'bytenr', useful +for debugging (disables the '-f' option) + -If there are multiple options specified, only the last one is applies. +If there are multiple options specified, only the last one applies. + -F|--force:::: -attempt to print the superblock even if thre's no valid BTRFS signature found +attempt to print the superblock even if thre's no valid BTRFS signature found, +the result may be completely wrong if the data do not resemble a superblock + -The result may be completely wrong if the data do not resemble a superblock. +-s|--super <bytenr>:::: +(see compatibility note above) + --s <bytenr>:::: -specify offset to a superblock in a non-standard location at 'bytenr', useful -for debugging (disables the '-f' option) +specify which mirror to print, valid values are 0, 1 and 2 and the superblock +must be present on the device with a valid signature, can be used together with +'--force' *dump-tree* [options] <device>:: (replaces the standalone tool *btrfs-debug-tree*) diff --git a/Documentation/btrfs-man5.asciidoc b/Documentation/btrfs-man5.asciidoc index a1f364e0..caa9390b 100644 --- a/Documentation/btrfs-man5.asciidoc +++ b/Documentation/btrfs-man5.asciidoc @@ -214,15 +214,18 @@ parameters, eg. 'panic', 'oops' or 'crashkernel'. *flushoncommit*:: *noflushoncommit*:: -(default: on) +(default: off) + This 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 application's perspective (i.e., it -includes all completed file system operations). This was previously the -behavior only when a snapshot was created. +as part of the current commit, effectively a full filesystem sync. ++ +This makes the committed state a fully consistent view of the file system from +the application's perspective (i.e., it includes all completed file system +operations). This was previously the behavior only when a snapshot was +created. + -Disabling flushing may improve performance but is not crash-safe. +When off, the filesystem is consistent but buffered writes may last more than +one transaction commit. *fragment='type'*:: (depends on compile-time option BTRFS_DEBUG, since: 4.4, default: off) diff --git a/Documentation/btrfs-subvolume.asciidoc b/Documentation/btrfs-subvolume.asciidoc index 2044b07d..0a1ca003 100644 --- a/Documentation/btrfs-subvolume.asciidoc +++ b/Documentation/btrfs-subvolume.asciidoc @@ -47,7 +47,7 @@ do not affect the files in the original subvolume. SUBCOMMAND ----------- -*create* [-i <qgroupid>] [<dest>]<name>:: +*create* [-i <qgroupid>] [<dest>/]<name>:: Create a subvolume <name> in <dest>. + If <dest> is not given, subvolume <name> will be created in the current @@ -130,14 +130,14 @@ list subvolumes in the filesystem that its generation is neither \'+' nor \'-', it means = value. -C [+|-]<value>:::: list subvolumes in the filesystem that its ogeneration is ->=, \<= or = value. The usage is the same to '-g' option. +>=, \<= or = value. The usage is the same to '-G' option. --sort=rootid,gen,ogen,path:::: list subvolumes in order by specified items. you can add \'\+' or \'-' in front of each items, \'+' means ascending, \'-' means descending. The default is ascending. + for --sort you can combine some items together by \',', just like --sort=+ogen,-gen,path,rootid. +--sort=+ogen,-gen,path,rootid. *set-default* <id> <path>:: Set the subvolume of the filesystem <path> which is mounted as diff --git a/Documentation/mkfs.btrfs.asciidoc b/Documentation/mkfs.btrfs.asciidoc index 98fe694b..6515e145 100644 --- a/Documentation/mkfs.btrfs.asciidoc +++ b/Documentation/mkfs.btrfs.asciidoc @@ -263,18 +263,30 @@ There are the following block group types available: .2+^.<h| Profile 3+^.^h| Redundancy .2+^.<h| Min/max devices ^.^h| Copies ^.^h| Parity ^.<h| Striping | single | 1 | | | 1/any -| DUP | 2 / 1 device | | | 1/any ^(see note)^ +| DUP | 2 / 1 device | | | 1/any ^(see note 1)^ | RAID0 | | | 1 to N | 2/any | RAID1 | 2 | | | 2/any | RAID10 | 2 | | 1 to N | 4/any -| RAID5 | 1 | 1 | 2 to N - 1 | 2/any -| RAID6 | 1 | 2 | 3 to N - 2 | 3/any +| RAID5 | 1 | 1 | 2 to N - 1 | 2/any ^(see note 2)^ +| RAID6 | 1 | 2 | 3 to N - 2 | 3/any ^(see note 3)^ |============================================================= -'Note:' DUP may exist on more than 1 device if it starts on a single device and +WARNING: It's not recommended to build btrfs with RAID0/1/10/5/6 prfiles on +partitions from the same device. Neither redundancy nor performance will be +improved. + +'Note 1:' DUP may exist on more than 1 device if it starts on a single device and another one is added. Since version 4.5.1, *mkfs.btrfs* will let you create DUP on multiple devices. +'Note 2:' It's not recommended to use 2 devices with RAID5. In that case, +parity stripe will contain the same data as the data stripe, making RAID5 +degraded to RAID1 with more overhead. + +'Note 3:' It's also not recommended to use 3 devices with RAID6, unless you +want to get effectively 3 copies in a RAID1-like manner (but not exactly that). +N-copies RAID1 is not implemented. + DUP PROFILES ON A SINGLE DEVICE ------------------------------- |