1 .TH BTRFS 8 "" "btrfs" "btrfs"
3 .\" Man page written by Goffredo Baroncelli <kreijack@inwind.it> (Feb 2010)
6 btrfs \- control a btrfs filesystem
8 \fBbtrfs\fP \fBsubvolume snapshot\fP\fI [-r] <source> [<dest>/]<name>\fP
10 \fBbtrfs\fP \fBsubvolume delete\fP\fI <subvolume> [<subvolume>...]\fP
12 \fBbtrfs\fP \fBsubvolume create\fP\fI [<dest>/]<name>\fP
14 \fBbtrfs\fP \fBsubvolume list\fP\fI [-acgoprts] [-G [+|-]value] [-C [+|-]value] [--sort=rootid,gen,ogen,path] <path>\fP
16 \fBbtrfs\fP \fBsubvolume set-default\fP\fI <id> <path>\fP
18 \fBbtrfs\fP \fBsubvolume get-default\fP\fI <path>\fP
20 \fBbtrfs\fP \fBsubvolume find-new\fP\fI <subvolume> <last_gen>\fP
22 \fBbtrfs\fP \fBsubvolume show\fP\fI <path>\fP
24 \fBbtrfs\fP \fBfilesystem defragment\fP -c[zlib|lzo] [-l \fIlen\fR] \
25 [-s \fIstart\fR] [-t \fIsize\fR] -[vf] <\fIfile\fR>|<\fIdir\fR> \
26 [<\fIfile\fR>|<\fIdir\fR>...]
28 \fBbtrfs\fP \fBfilesystem sync\fP\fI <path> \fP
30 \fBbtrfs\fP \fBfilesystem resize\fP\fI [devid:][+/\-]<size>[gkm]|[devid:]max <filesystem>\fP
32 \fBbtrfs\fP \fBfilesystem label\fP\fI <dev> [newlabel]\fP
34 \fBbtrfs\fP \fBfilesystem show\fP\fI [--all-devices|<uuid>|<label>]\fP
36 \fBbtrfs\fP \fBfilesystem balance\fP\fI <path> \fP
38 \fBbtrfs\fP \fBdevice scan\fP\fI [--all-devices|<device> [<device>...]]\fP
40 \fBbtrfs\fP \fBdevice stats\fP [-z] {\fI<path>\fP|\fI<device>\fP}
42 \fBbtrfs\fP \fBdevice add\fP\fI <device> [<device>...] <path> \fP
44 \fBbtrfs\fP \fBdevice delete\fP\fI <device> [<device>...] <path> \fP
46 \fBbtrfs\fP \fBreplace start\fP \fI[-Bfr] <srcdev>|<devid> <targetdev> <path>\fP
48 \fBbtrfs\fP \fBreplace status\fP \fI[-1] <path>\fP
50 \fBbtrfs\fP \fBreplace cancel\fP \fI<path>\fP
52 \fBbtrfs\fP \fBscrub start\fP [-Bdqru] [-c ioprio_class -n ioprio_classdata] {\fI<path>\fP|\fI<device>\fP}
54 \fBbtrfs\fP \fBscrub cancel\fP {\fI<path>\fP|\fI<device>\fP}
56 \fBbtrfs\fP \fBscrub resume\fP [-Bdqru] [-c ioprio_class -n ioprio_classdata] {\fI<path>\fP|\fI<device>\fP}
58 \fBbtrfs\fP \fBscrub status\fP [-d] {\fI<path>\fP|\fI<device>\fP}
60 \fBbtrfs\fP \fBinspect-internal inode-resolve\fP [-v] \fI<inode>\fP \fI<path>\fP
62 \fBbtrfs\fP \fBinspect-internal logical-resolve\fP
63 [-Pv] [-s size] \fI<logical>\fP \fI<path>\fP
65 \fBbtrfs\fP \fBinspect-internal subvolid-resolve\fP \fI<subvolid>\fP \fI<path>\fP
67 \fBbtrfs\fP \fBqgroup assign\fP \fI<src>\fP \fI<dst>\fP \fI<path>\fP
69 \fBbtrfs\fP \fBqgroup remove\fP \fI<src>\fP \fI<dst>\fP \fI<path>\fP
71 \fBbtrfs\fP \fBqgroup create\fP \fI<qgroupid>\fP \fI<path>\fP
73 \fBbtrfs\fP \fBqgroup destroy\fP \fI<qgroupid>\fP \fI<path>\fP
75 \fBbtrfs\fP \fBqgroup show\fP \fI<path>\fP
77 \fBbtrfs\fP \fBqgroup limit\fP [options] \fI<size>\fP|\fBnone\fP [\fI<qgroupid>\fP] \fI<path>\fP
79 \fBbtrfs\fP \fBhelp|\-\-help \fP\fI\fP
81 \fBbtrfs\fP \fB<command> \-\-help \fP\fI\fP
85 is used to control the filesystem and the files and directories stored. It is
86 the tool to create or destroy a snapshot or a subvolume for the
87 filesystem, to defrag a file or a directory, flush the data to the disk,
88 to resize the filesystem, to scan the device.
90 It is possible to abbreviate the commands unless the commands are ambiguous.
91 For example: it is possible to run
94 .I btrfs subvolume snapshot.
97 is not allowed, because
99 may be interpreted both as
105 returns filesystem sync
106 If a command is terminated by
108 , the detailed help is showed. If the passed command matches more commands,
109 detailed help of all the matched commands is showed. For example
111 shows the help of all
118 \fBsubvolume snapshot\fR\fI [-r] <source> [<dest>/]<name>\fR
119 Create a writable/readonly snapshot of the subvolume \fI<source>\fR with the
120 name \fI<name>\fR in the \fI<dest>\fR directory. If \fI<source>\fR is not a
121 subvolume, \fBbtrfs\fR returns an error. If \fI-r\fR is given, the snapshot
125 \fBsubvolume delete\fR\fI <subvolume> [<subvolume>...]\fR
126 Delete the subvolume \fI<subvolume>\fR. If \fI<subvolume>\fR is not a
127 subvolume, \fBbtrfs\fR returns an error.
130 \fBsubvolume create\fR\fI [<dest>/]<name>\fR
131 Create a subvolume in \fI<dest>\fR (or in the current directory if
132 \fI<dest>\fR is omitted).
135 \fBsubvolume list\fR\fI [-acgoprts] [-G [+|-]value] [-C [+|-]value] [--sort=rootid,gen,ogen,path] <path>\fR
137 List the subvolumes present in the filesystem \fI<path>\fR. For every
138 subvolume the following information is shown by default.
139 ID <ID> top level <ID> path <path>
140 where path is the relative path of the subvolume to the \fItop level\fR
143 The subvolume's ID may be used by the \fBsubvolume set-default\fR command, or
144 at mount time via the \fIsubvolid=\fR option.
145 If \fI-p\fR is given, then \fIparent <ID>\fR is added to the output between ID
146 and top level. The parent's ID may be used at mount time via the
147 \fIsubvolrootid=\fR option.
149 \fB-t\fP print the result as a table.
151 \fB-a\fP print all the subvolumes in the filesystem and distinguish between
152 absolute and relative path with respect to the given <path>.
154 \fB-c\fP print the ogeneration of the subvolume, aliases: ogen or origin generation
156 \fB-g\fP print the generation of the subvolume
158 \fB-u\fP print the UUID of the subvolume
160 \fB-o\fP print only subvolumes bellow specified <path>.
162 \fB-r\fP only readonly subvolumes in the filesystem will be listed.
164 \fB-s\fP only snapshot subvolumes in the filesystem will be listed.
167 list subvolumes in the filesystem that its generation is
168 >=, <= or = value. '+' means >= value, '-' means <= value, If there is
169 neither '+' nor '-', it means = value.
172 list subvolumes in the filesystem that its ogeneration is
173 >=, <= or = value. The usage is the same to '-g' option.
175 \fB--sort=rootid,gen,ogen,path\fP
176 list subvolumes in order by specified items.
177 you can add '+' or '-' in front of each items, '+' means ascending, '-'
178 means descending. The default is ascending.
180 for \fB--sort\fP you can combine some items together by ',', just like
181 \f--sort=+ogen,-gen,path,rootid\fR.
185 \fBsubvolume set-default\fR\fI <id> <path>\fR
186 Set the subvolume of the filesystem \fI<path>\fR which is mounted as
187 \fIdefault\fR. The subvolume is identified by \fI<id>\fR, which
188 is returned by the \fBsubvolume list\fR command.
191 \fBsubvolume get-default\fR\fI <path>\fR
192 Get the default subvolume of the filesystem \fI<path>\fR. The output format
193 is similar to \fBsubvolume list\fR command.
196 \fBsubvolume find-new\fR\fI <subvolume> <last_gen>\fR
197 List the recently modified files in a subvolume, after \fI<last_gen>\fR ID.
200 \fBsubvolume show\fR\fI <path>\fR
201 Show information of a given subvolume in the \fI<path>\fR.
204 \fBfilesystem defragment\fP -c[zlib|lzo] [-l \fIlen\fR] [-s \fIstart\fR] \
205 [-t \fIsize\fR] -[vf] <\fIfile\fR>|<\fIdir\fR> [<\fIfile\fR>|<\fIdir\fR>...]
207 Defragment file data and/or directory metadata. To defragment all files in a
208 directory you have to specify each one on its own or use your shell wildcards.
210 The start position and the number of bytes to defragment can be specified by
211 \fIstart\fR and \fIlen\fR. Any extent bigger than threshold will be
212 considered already defragged. Use 0 to take the kernel default, and use 1 to
213 say every single extent must be rewritten. You can also turn on compression in
214 defragment operations.
218 \fB-c\fP compress file contents while defragmenting
220 \fB-f\fP flush filesystem after defragmenting
222 \fB-s start\fP defragment only from byte \fIstart\fR onward
224 \fB-l len\fP defragment only up to \fIlen\fR bytes
226 \fB-t size\fP defragment only files at least \fIsize\fR bytes big
228 For \fBstart\fP, \fBlen\fP, \fBsize\fP it is possible to append a suffix
229 like \fBk\fP for 1 KBytes, \fBm\fP for 1 MBytes...
231 NOTE: defragmenting with kernels up to 2.6.37 will unlink COW-ed copies of data,
232 don't use it if you use snapshots, have de-duplicated your data or made
233 copies with \fBcp --reflink\fP.
236 \fBfilesystem sync\fR\fI <path> \fR
237 Force a sync for the filesystem identified by \fI<path>\fR.
241 .\" Some wording are extracted by the resize2fs man page
244 \fBfilesystem resize\fR\fI [devid:][+/\-]<size>[gkm]|[devid:]max <path>\fR
245 Resize a filesystem identified by \fI<path>\fR for the underlying device
246 \fIdevid\fR. The \fIdevid\fR can be found with \fBbtrfs filesystem show\fR and
247 defaults to 1 if not specified.
248 The \fI<size>\fR parameter specifies the new size of the filesystem.
249 If the prefix \fI+\fR or \fI\-\fR is present the size is increased or decreased
250 by the quantity \fI<size>\fR.
251 If no units are specified, the unit of the \fI<size>\fR parameter defaults to
252 bytes. Optionally, the size parameter may be suffixed by one of the following
253 units designators: 'K', 'M', or 'G', kilobytes, megabytes, or gigabytes,
256 If 'max' is passed, the filesystem will occupy all available space on the
259 The \fBresize\fR command \fBdoes not\fR manipulate the size of underlying
260 partition. If you wish to enlarge/reduce a filesystem, you must make sure you
261 can expand the partition before enlarging the filesystem and shrink the
262 partition after reducing the size of the filesystem. This can done using
263 \fBfdisk(8)\fR or \fBparted(8)\fR to delete the existing partition and recreate
264 it with the new desired size. When recreating the partition make sure to use
265 the same starting disk cylinder as before.
268 \fBfilesystem label\fP\fI <dev> [newlabel]\fP
269 Show or update the label of a filesystem. \fI<dev>\fR is used to identify the
271 If a \fInewlabel\fR optional argument is passed, the label is changed. The
272 following constraints exist for a label:
274 - the maximum allowable length shall be less or equal than 256 chars
276 - the label shall not contain the '/' or '\\' characters.
278 NOTE: Currently there are the following limitations:
280 - the filesystem has to be unmounted
282 - the filesystem should not have more than one device.
285 \fBfilesystem show\fR [--all-devices|<uuid>|<label>]\fR
286 Show the btrfs filesystem with some additional info. If no \fIUUID\fP or
287 \fIlabel\fP is passed, \fBbtrfs\fR show info of all the btrfs filesystem.
288 If \fB--all-devices\fP is passed, all the devices under /dev are scanned;
289 otherwise the devices list is extracted from the /proc/partitions file.
292 \fBfilesystem balance\fR \fI<path>\fR
293 Balance the chunks of the filesystem identified by \fI<path>\fR
297 \fBdevice stats\fP [-z] {\fI<path>\fP|\fI<device>\fP}
298 Read and print the device IO stats for all devices of the filesystem
299 identified by \fI<path>\fR or for a single \fI<device>\fR.
305 Reset stats to zero after reading them.
309 \fBdevice add\fR\fI <dev> [<dev>..] <path>\fR
310 Add device(s) to the filesystem identified by \fI<path>\fR.
313 \fBdevice delete\fR\fI <dev> [<dev>..] <path>\fR
314 Remove device(s) from a filesystem identified by \fI<path>\fR.
317 \fBdevice scan\fR \fI[--all-devices|<device> [<device>...]\fR
318 If one or more devices are passed, these are scanned for a btrfs filesystem.
319 If no devices are passed, \fBbtrfs\fR scans all the block devices listed
320 in the /proc/partitions file.
321 Finally, if \fB--all-devices\fP is passed, all the devices under /dev are
325 \fBreplace start\fR \fI[-Bfr] <srcdev>|<devid> <targetdev> <path>\fR
326 Replace device of a btrfs filesystem.
327 On a live filesystem, duplicate the data to the target device which
328 is currently stored on the source device. If the source device is not
329 available anymore, or if the \fB-r\fR option is set, the data is built
330 only using the RAID redundancy mechanisms. After completion of the
331 operation, the source device is removed from the filesystem.
332 If the \fIsrcdev\fR is a numerical value, it is assumed to be the device id
333 of the filesystem which is mounted at mount_point, otherwise is is
334 the path to the source device. If the source device is disconnected,
335 from the system, you have to use the \fIdevid\fR parameter format.
336 The targetdev needs to be same size or larger than the \fIsrcdev\fR.
342 only read from \fIsrcdev\fR if no other zero-defect mirror exists (enable
343 this if your drive has lots of read errors, the access would be very slow)
346 force using and overwriting \fItargetdev\fR even if it looks like
347 containing a valid btrfs filesystem. A valid filesystem is
348 assumed if a btrfs superblock is found which contains a
349 correct checksum. Devices which are currently mounted are
350 never allowed to be used as the \fItargetdev\fR
357 \fBreplace status\fR \fI[-1] <path>\fR
358 Print status and progress information of a running device replace operation.
364 print once instead of print continously until the replace
365 operation finishes (or is canceled)
369 \fBreplace cancel\fR \fI<path>\fR
370 Cancel a running device replace operation.
373 \fBscrub start\fP [-Bdqru] {\fI<path>\fP|\fI<device>\fP}
374 \fBscrub start\fP [-Bdqru] [-c ioprio_class -n ioprio_classdata] {\fI<path>\fP|\fI<device>\fP}
375 Start a scrub on all devices of the filesystem identified by \fI<path>\fR or on
376 a single \fI<device>\fR. Without options, scrub is started as a background
377 process. Progress can be obtained with the \fBscrub status\fR command. Scrubbing
378 involves reading all data from all disks and verifying checksums. Errors are
379 corrected along the way if possible.
381 The default IO priority of scrub is the idle class. The priority can be configured similar to the
388 Do not background and print scrub statistics when finished.
390 Print separate statistics for each device of the filesystem (-B only).
392 Quiet. Omit error messages and statistics.
394 Read only mode. Do not attempt to correct anything.
396 Scrub unused space as well. (NOT IMPLEMENTED)
398 Set IO priority class (see
402 Set IO priority classdata (see
408 \fBscrub cancel\fP {\fI<path>\fP|\fI<device>\fP}
409 If a scrub is running on the filesystem identified by \fI<path>\fR, cancel it.
410 Progress is saved in the scrub progress file and scrubbing can be resumed later
411 using the \fBscrub resume\fR command.
412 If a \fI<device>\fR is given, the corresponding filesystem is found and
413 \fBscrub cancel\fP behaves as if it was called on that filesystem.
416 \fBscrub resume\fP [-Bdqru] [-c ioprio_class -n ioprio_classdata] {\fI<path>\fP|\fI<device>\fP}
417 Resume a canceled or interrupted scrub cycle on the filesystem identified by
418 \fI<path>\fR or on a given \fI<device>\fR. Does not start a new scrub if the
419 last scrub finished successfully.
424 see \fBscrub start\fP.
428 \fBscrub status\fP [-d] {\fI<path>\fP|\fI<device>\fP}
429 Show status of a running scrub for the filesystem identified by \fI<path>\fR or
430 for the specified \fI<device>\fR.
431 If no scrub is running, show statistics of the last finished or canceled scrub
432 for that filesystem or device.
437 Print separate statistics for each device of the filesystem.
441 \fBinspect-internal inode-resolve\fP [-v] \fI<inode>\fP \fI<path>\fP
442 Resolves an <inode> in subvolume <path> to all filesystem paths.
447 verbose mode. print count of returned paths and ioctl() return value
451 \fBinspect-internal logical-resolve\fP [-Pv] [-s bufsize] \fI<logical>\fP \fI<path>\fP
452 Resolves a <logical> address in the filesystem mounted at <path> to all inodes.
453 By default, each inode is then resolved to a file system path (similar to the
454 \fBinode-resolve\fP subcommand).
459 skip the path resolving and print the inodes instead
461 verbose mode. print count of returned paths and all ioctl() return values
463 set inode container's size. This is used to increase inode container's size in case it is
464 not enough to read all the resolved results. The max value one can set is 64k.
468 \fBinspect-internal subvolid-resolve\fP \fI<subvolid>\fP \fI<path>\fP
469 Get file system paths for the given subvolume ID.
472 \fBbtrfs qgroup assign\fP \fI<src>\fP \fI<dst>\fP \fI<path>\fP
473 Enable subvolume qgroup support for a filesystem.
476 \fBbtrfs qgroup remove\fP \fI<src>\fP \fI<dst>\fP \fI<path>\fP
477 Remove a subvol from a quota group.
480 \fBbtrfs qgroup create\fP \fI<qgroupid>\fP \fI<path>\fP
481 Create a subvolume quota group.
484 \fBbtrfs qgroup destroy\fP \fI<qgroupid>\fP \fI<path>\fP
485 Destroy a subvolume quota group.
488 \fBbtrfs qgroup show\fP \fI<path>\fP
489 Show all subvolume quota groups.
492 \fBbtrfs\fP \fBqgroup limit\fP [options] \fI<size>\fP|\fBnone\fP [\fI<qgroupid>\fP] \fI<path>\fP
493 Limit the size of a subvolume quota group.
497 \fBbtrfs\fR returns a zero exist status if it succeeds. Non zero is returned in
502 is part of btrfs-progs. Btrfs filesystem is currently under heavy development,
503 and not suitable for any uses other than benchmarking and review.
504 Please refer to the btrfs wiki http://btrfs.wiki.kernel.org for