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Linus Torvalds1da177e2005-04-16 15:20:36 -07001
2The SGI XFS Filesystem
3======================
4
5XFS is a high performance journaling filesystem which originated
6on the SGI IRIX platform. It is completely multi-threaded, can
7support large files and large filesystems, extended attributes,
8variable block sizes, is extent based, and makes extensive use of
9Btrees (directories, extents, free space) to aid both performance
10and scalability.
11
12Refer to the documentation at http://oss.sgi.com/projects/xfs/
13for further details. This implementation is on-disk compatible
14with the IRIX version of XFS.
15
16
17Mount Options
18=============
19
20When mounting an XFS filesystem, the following options are accepted.
Dave Chinner3e5b7d82013-07-10 07:03:59 +100021For boolean mount options, the names with the (*) suffix is the
22default behaviour.
Linus Torvalds1da177e2005-04-16 15:20:36 -070023
Nathan Scottfc97bbf2005-11-03 13:46:43 +110024 allocsize=size
25 Sets the buffered I/O end-of-file preallocation size when
26 doing delayed allocation writeout (default size is 64KiB).
27 Valid values for this option are page size (typically 4KiB)
28 through to 1GiB, inclusive, in power-of-2 increments.
29
Dave Chinner3e5b7d82013-07-10 07:03:59 +100030 The default behaviour is for dynamic end-of-file
31 preallocation size, which uses a set of heuristics to
32 optimise the preallocation size based on the current
33 allocation patterns within the file and the access patterns
34 to the file. Specifying a fixed allocsize value turns off
35 the dynamic behaviour.
36
37 attr2
38 noattr2
39 The options enable/disable an "opportunistic" improvement to
40 be made in the way inline extended attributes are stored
41 on-disk. When the new form is used for the first time when
42 attr2 is selected (either when setting or removing extended
43 attributes) the on-disk superblock feature bit field will be
44 updated to reflect this format being in use.
45
46 The default behaviour is determined by the on-disk feature
47 bit indicating that attr2 behaviour is active. If either
48 mount option it set, then that becomes the new default used
49 by the filesystem.
Nathan Scottfc97bbf2005-11-03 13:46:43 +110050
Dave Chinnerd3eaace2013-06-05 12:09:09 +100051 CRC enabled filesystems always use the attr2 format, and so
52 will reject the noattr2 mount option if it is set.
53
Dave Chinner3e5b7d82013-07-10 07:03:59 +100054 barrier (*)
55 nobarrier
56 Enables/disables the use of block layer write barriers for
57 writes into the journal and for data integrity operations.
58 This allows for drive level write caching to be enabled, for
59 devices that support write barriers.
Nathan Scottfc97bbf2005-11-03 13:46:43 +110060
Christoph Hellwige84661a2011-05-20 13:45:32 +000061 discard
Dave Chinner3e5b7d82013-07-10 07:03:59 +100062 nodiscard (*)
63 Enable/disable the issuing of commands to let the block
64 device reclaim space freed by the filesystem. This is
65 useful for SSD devices, thinly provisioned LUNs and virtual
66 machine images, but may have a performance impact.
Christoph Hellwige84661a2011-05-20 13:45:32 +000067
Dave Chinner3e5b7d82013-07-10 07:03:59 +100068 Note: It is currently recommended that you use the fstrim
69 application to discard unused blocks rather than the discard
70 mount option because the performance impact of this option
71 is quite severe.
Nathan Scottfc97bbf2005-11-03 13:46:43 +110072
Dave Chinner3e5b7d82013-07-10 07:03:59 +100073 grpid/bsdgroups
74 nogrpid/sysvgroups (*)
75 These options define what group ID a newly created file
76 gets. When grpid is set, it takes the group ID of the
77 directory in which it is created; otherwise it takes the
78 fsgid of the current process, unless the directory has the
79 setgid bit set, in which case it takes the gid from the
80 parent directory, and also gets the setgid bit set if it is
81 a directory itself.
Nathan Scottfc97bbf2005-11-03 13:46:43 +110082
Dave Chinner3e5b7d82013-07-10 07:03:59 +100083 filestreams
84 Make the data allocator use the filestreams allocation mode
85 across the entire filesystem rather than just on directories
86 configured to use it.
Linus Torvalds1da177e2005-04-16 15:20:36 -070087
Dave Chinner3e5b7d82013-07-10 07:03:59 +100088 ikeep
89 noikeep (*)
90 When ikeep is specified, XFS does not delete empty inode
91 clusters and keeps them around on disk. When noikeep is
92 specified, empty inode clusters are returned to the free
93 space pool.
Carlos Maiolinoc99abb82012-10-18 12:28:58 -030094
95 inode32
Dave Chinner3e5b7d82013-07-10 07:03:59 +100096 inode64 (*)
97 When inode32 is specified, it indicates that XFS limits
98 inode creation to locations which will not result in inode
99 numbers with more than 32 bits of significance.
Nathan Scottfc97bbf2005-11-03 13:46:43 +1100100
Dave Chinner3e5b7d82013-07-10 07:03:59 +1000101 When inode64 is specified, it indicates that XFS is allowed
102 to create inodes at any location in the filesystem,
103 including those which will result in inode numbers occupying
104 more than 32 bits of significance.
105
106 inode32 is provided for backwards compatibility with older
107 systems and applications, since 64 bits inode numbers might
108 cause problems for some applications that cannot handle
109 large inode numbers. If applications are in use which do
110 not handle inode numbers bigger than 32 bits, the inode32
111 option should be specified.
112
113
114 largeio
115 nolargeio (*)
Nathan Scottfc97bbf2005-11-03 13:46:43 +1100116 If "nolargeio" is specified, the optimal I/O reported in
Dave Chinner3e5b7d82013-07-10 07:03:59 +1000117 st_blksize by stat(2) will be as small as possible to allow
118 user applications to avoid inefficient read/modify/write
119 I/O. This is typically the page size of the machine, as
120 this is the granularity of the page cache.
121
122 If "largeio" specified, a filesystem that was created with a
123 "swidth" specified will return the "swidth" value (in bytes)
124 in st_blksize. If the filesystem does not have a "swidth"
125 specified but does specify an "allocsize" then "allocsize"
126 (in bytes) will be returned instead. Otherwise the behaviour
127 is the same as if "nolargeio" was specified.
Nathan Scottfc97bbf2005-11-03 13:46:43 +1100128
Linus Torvalds1da177e2005-04-16 15:20:36 -0700129 logbufs=value
Dave Chinner3e5b7d82013-07-10 07:03:59 +1000130 Set the number of in-memory log buffers. Valid numbers
131 range from 2-8 inclusive.
132
133 The default value is 8 buffers.
134
135 If the memory cost of 8 log buffers is too high on small
136 systems, then it may be reduced at some cost to performance
137 on metadata intensive workloads. The logbsize option below
Masanari Iida9ed354b2013-08-20 20:33:17 +0900138 controls the size of each buffer and so is also relevant to
Dave Chinner3e5b7d82013-07-10 07:03:59 +1000139 this case.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700140
141 logbsize=value
Dave Chinner3e5b7d82013-07-10 07:03:59 +1000142 Set the size of each in-memory log buffer. The size may be
143 specified in bytes, or in kilobytes with a "k" suffix.
144 Valid sizes for version 1 and version 2 logs are 16384 (16k)
145 and 32768 (32k). Valid sizes for version 2 logs also
146 include 65536 (64k), 131072 (128k) and 262144 (256k). The
147 logbsize must be an integer multiple of the log
148 stripe unit configured at mkfs time.
149
150 The default value for for version 1 logs is 32768, while the
151 default value for version 2 logs is MAX(32768, log_sunit).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700152
153 logdev=device and rtdev=device
154 Use an external log (metadata journal) and/or real-time device.
155 An XFS filesystem has up to three parts: a data section, a log
156 section, and a real-time section. The real-time section is
157 optional, and the log section can be separate from the data
158 section or contained within it.
159
160 noalign
Dave Chinner3e5b7d82013-07-10 07:03:59 +1000161 Data allocations will not be aligned at stripe unit
162 boundaries. This is only relevant to filesystems created
163 with non-zero data alignment parameters (sunit, swidth) by
164 mkfs.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700165
166 norecovery
167 The filesystem will be mounted without running log recovery.
168 If the filesystem was not cleanly unmounted, it is likely to
169 be inconsistent when mounted in "norecovery" mode.
170 Some files or directories may not be accessible because of this.
171 Filesystems mounted "norecovery" must be mounted read-only or
172 the mount will fail.
173
174 nouuid
Dave Chinner3e5b7d82013-07-10 07:03:59 +1000175 Don't check for double mounted file systems using the file
176 system uuid. This is useful to mount LVM snapshot volumes,
177 and often used in combination with "norecovery" for mounting
178 read-only snapshots.
179
180 noquota
181 Forcibly turns off all quota accounting and enforcement
182 within the filesystem.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700183
Nathan Scottfc97bbf2005-11-03 13:46:43 +1100184 uquota/usrquota/uqnoenforce/quota
Linus Torvalds1da177e2005-04-16 15:20:36 -0700185 User disk quota accounting enabled, and limits (optionally)
Nathan Scottfc97bbf2005-11-03 13:46:43 +1100186 enforced. Refer to xfs_quota(8) for further details.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700187
Nathan Scottfc97bbf2005-11-03 13:46:43 +1100188 gquota/grpquota/gqnoenforce
Linus Torvalds1da177e2005-04-16 15:20:36 -0700189 Group disk quota accounting enabled and limits (optionally)
Nathan Scottfc97bbf2005-11-03 13:46:43 +1100190 enforced. Refer to xfs_quota(8) for further details.
191
192 pquota/prjquota/pqnoenforce
193 Project disk quota accounting enabled and limits (optionally)
194 enforced. Refer to xfs_quota(8) for further details.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700195
196 sunit=value and swidth=value
Dave Chinner3e5b7d82013-07-10 07:03:59 +1000197 Used to specify the stripe unit and width for a RAID device
198 or a stripe volume. "value" must be specified in 512-byte
199 block units. These options are only relevant to filesystems
200 that were created with non-zero data alignment parameters.
201
202 The sunit and swidth parameters specified must be compatible
203 with the existing filesystem alignment characteristics. In
204 general, that means the only valid changes to sunit are
205 increasing it by a power-of-2 multiple. Valid swidth values
206 are any integer multiple of a valid sunit value.
207
208 Typically the only time these mount options are necessary if
209 after an underlying RAID device has had it's geometry
210 modified, such as adding a new disk to a RAID5 lun and
211 reshaping it.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700212
Nathan Scottfc97bbf2005-11-03 13:46:43 +1100213 swalloc
214 Data allocations will be rounded up to stripe width boundaries
215 when the current end of file is being extended and the file
216 size is larger than the stripe width size.
217
Dave Chinner3e5b7d82013-07-10 07:03:59 +1000218 wsync
219 When specified, all filesystem namespace operations are
220 executed synchronously. This ensures that when the namespace
221 operation (create, unlink, etc) completes, the change to the
222 namespace is on stable storage. This is useful in HA setups
223 where failover must not result in clients seeing
224 inconsistent namespace presentation during or after a
225 failover event.
226
227
228Deprecated Mount Options
229========================
230
231 delaylog/nodelaylog
232 Delayed logging is the only logging method that XFS supports
233 now, so these mount options are now ignored.
234
235 Due for removal in 3.12.
236
237 ihashsize=value
238 In memory inode hashes have been removed, so this option has
239 no function as of August 2007. Option is deprecated.
240
241 Due for removal in 3.12.
242
243 irixsgid
244 This behaviour is now controlled by a sysctl, so the mount
245 option is ignored.
246
247 Due for removal in 3.12.
248
249 osyncisdsync
250 osyncisosync
251 O_SYNC and O_DSYNC are fully supported, so there is no need
252 for these options any more.
253
254 Due for removal in 3.12.
Nathan Scottfc97bbf2005-11-03 13:46:43 +1100255
Linus Torvalds1da177e2005-04-16 15:20:36 -0700256sysctls
257=======
258
259The following sysctls are available for the XFS filesystem:
260
261 fs.xfs.stats_clear (Min: 0 Default: 0 Max: 1)
Nathan Scottfc97bbf2005-11-03 13:46:43 +1100262 Setting this to "1" clears accumulated XFS statistics
Linus Torvalds1da177e2005-04-16 15:20:36 -0700263 in /proc/fs/xfs/stat. It then immediately resets to "0".
Nathan Scottfc97bbf2005-11-03 13:46:43 +1100264
Linus Torvalds1da177e2005-04-16 15:20:36 -0700265 fs.xfs.xfssyncd_centisecs (Min: 100 Default: 3000 Max: 720000)
Dave Chinner3e5b7d82013-07-10 07:03:59 +1000266 The interval at which the filesystem flushes metadata
267 out to disk and runs internal cache cleanup routines.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700268
Dave Chinner3e5b7d82013-07-10 07:03:59 +1000269 fs.xfs.filestream_centisecs (Min: 1 Default: 3000 Max: 360000)
270 The interval at which the filesystem ages filestreams cache
271 references and returns timed-out AGs back to the free stream
272 pool.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700273
Dave Chinner3e5b7d82013-07-10 07:03:59 +1000274 fs.xfs.speculative_prealloc_lifetime
275 (Units: seconds Min: 1 Default: 300 Max: 86400)
276 The interval at which the background scanning for inodes
277 with unused speculative preallocation runs. The scan
278 removes unused preallocation from clean inodes and releases
279 the unused space back to the free pool.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700280
281 fs.xfs.error_level (Min: 0 Default: 3 Max: 11)
282 A volume knob for error reporting when internal errors occur.
283 This will generate detailed messages & backtraces for filesystem
284 shutdowns, for example. Current threshold values are:
285
286 XFS_ERRLEVEL_OFF: 0
287 XFS_ERRLEVEL_LOW: 1
288 XFS_ERRLEVEL_HIGH: 5
289
Eric Sandeende8bd0e2015-02-06 09:20:29 +1100290 fs.xfs.panic_mask (Min: 0 Default: 0 Max: 255)
Nathan Scottfc97bbf2005-11-03 13:46:43 +1100291 Causes certain error conditions to call BUG(). Value is a bitmask;
Eric Sandeende8bd0e2015-02-06 09:20:29 +1100292 OR together the tags which represent errors which should cause panics:
Nathan Scottfc97bbf2005-11-03 13:46:43 +1100293
Linus Torvalds1da177e2005-04-16 15:20:36 -0700294 XFS_NO_PTAG 0
295 XFS_PTAG_IFLUSH 0x00000001
296 XFS_PTAG_LOGRES 0x00000002
297 XFS_PTAG_AILDELETE 0x00000004
298 XFS_PTAG_ERROR_REPORT 0x00000008
299 XFS_PTAG_SHUTDOWN_CORRUPT 0x00000010
300 XFS_PTAG_SHUTDOWN_IOERROR 0x00000020
301 XFS_PTAG_SHUTDOWN_LOGERROR 0x00000040
Eric Sandeende8bd0e2015-02-06 09:20:29 +1100302 XFS_PTAG_FSBLOCK_ZERO 0x00000080
Linus Torvalds1da177e2005-04-16 15:20:36 -0700303
Nathan Scottfc97bbf2005-11-03 13:46:43 +1100304 This option is intended for debugging only.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700305
306 fs.xfs.irix_symlink_mode (Min: 0 Default: 0 Max: 1)
307 Controls whether symlinks are created with mode 0777 (default)
308 or whether their mode is affected by the umask (irix mode).
309
310 fs.xfs.irix_sgid_inherit (Min: 0 Default: 0 Max: 1)
311 Controls files created in SGID directories.
312 If the group ID of the new file does not match the effective group
Nathan Scottfc97bbf2005-11-03 13:46:43 +1100313 ID or one of the supplementary group IDs of the parent dir, the
314 ISGID bit is cleared if the irix_sgid_inherit compatibility sysctl
Linus Torvalds1da177e2005-04-16 15:20:36 -0700315 is set.
316
Nathan Scottfc97bbf2005-11-03 13:46:43 +1100317 fs.xfs.inherit_sync (Min: 0 Default: 1 Max: 1)
318 Setting this to "1" will cause the "sync" flag set
319 by the xfs_io(8) chattr command on a directory to be
Linus Torvalds1da177e2005-04-16 15:20:36 -0700320 inherited by files in that directory.
321
Nathan Scottfc97bbf2005-11-03 13:46:43 +1100322 fs.xfs.inherit_nodump (Min: 0 Default: 1 Max: 1)
323 Setting this to "1" will cause the "nodump" flag set
324 by the xfs_io(8) chattr command on a directory to be
Linus Torvalds1da177e2005-04-16 15:20:36 -0700325 inherited by files in that directory.
326
Nathan Scottfc97bbf2005-11-03 13:46:43 +1100327 fs.xfs.inherit_noatime (Min: 0 Default: 1 Max: 1)
328 Setting this to "1" will cause the "noatime" flag set
329 by the xfs_io(8) chattr command on a directory to be
Linus Torvalds1da177e2005-04-16 15:20:36 -0700330 inherited by files in that directory.
Nathan Scottfc97bbf2005-11-03 13:46:43 +1100331
332 fs.xfs.inherit_nosymlinks (Min: 0 Default: 1 Max: 1)
333 Setting this to "1" will cause the "nosymlinks" flag set
334 by the xfs_io(8) chattr command on a directory to be
335 inherited by files in that directory.
336
Dave Chinner3e5b7d82013-07-10 07:03:59 +1000337 fs.xfs.inherit_nodefrag (Min: 0 Default: 1 Max: 1)
338 Setting this to "1" will cause the "nodefrag" flag set
339 by the xfs_io(8) chattr command on a directory to be
340 inherited by files in that directory.
341
Nathan Scottfc97bbf2005-11-03 13:46:43 +1100342 fs.xfs.rotorstep (Min: 1 Default: 1 Max: 256)
343 In "inode32" allocation mode, this option determines how many
344 files the allocator attempts to allocate in the same allocation
345 group before moving to the next allocation group. The intent
346 is to control the rate at which the allocator moves between
347 allocation groups when allocating extents for new files.
Dave Chinner3e5b7d82013-07-10 07:03:59 +1000348
349Deprecated Sysctls
350==================
351
Dave Chinner64af7a62015-01-09 10:47:43 +1100352None at present.
Dave Chinner3e5b7d82013-07-10 07:03:59 +1000353
Dave Chinner3e5b7d82013-07-10 07:03:59 +1000354
Dave Chinner64af7a62015-01-09 10:47:43 +1100355Removed Sysctls
356===============
Dave Chinner3e5b7d82013-07-10 07:03:59 +1000357
Dave Chinner64af7a62015-01-09 10:47:43 +1100358 Name Removed
359 ---- -------
360 fs.xfs.xfsbufd_centisec v3.20
361 fs.xfs.age_buffer_centisecs v3.20