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1da177e4 LT |
1 | |
2 | The SGI XFS Filesystem | |
3 | ====================== | |
4 | ||
5 | XFS is a high performance journaling filesystem which originated | |
6 | on the SGI IRIX platform. It is completely multi-threaded, can | |
7 | support large files and large filesystems, extended attributes, | |
8 | variable block sizes, is extent based, and makes extensive use of | |
9 | Btrees (directories, extents, free space) to aid both performance | |
10 | and scalability. | |
11 | ||
12 | Refer to the documentation at http://oss.sgi.com/projects/xfs/ | |
13 | for further details. This implementation is on-disk compatible | |
14 | with the IRIX version of XFS. | |
15 | ||
16 | ||
17 | Mount Options | |
18 | ============= | |
19 | ||
20 | When mounting an XFS filesystem, the following options are accepted. | |
3e5b7d8b DC |
21 | For boolean mount options, the names with the (*) suffix is the |
22 | default behaviour. | |
1da177e4 | 23 | |
fc97bbf3 NS |
24 | 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 | ||
3e5b7d8b DC |
30 | 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. | |
fc97bbf3 | 50 | |
d3eaace8 DC |
51 | CRC enabled filesystems always use the attr2 format, and so |
52 | will reject the noattr2 mount option if it is set. | |
53 | ||
3e5b7d8b DC |
54 | 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. | |
fc97bbf3 | 60 | |
e84661aa | 61 | discard |
3e5b7d8b DC |
62 | 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. | |
67 | ||
68 | 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. | |
72 | ||
73 | 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. | |
82 | ||
83 | 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. | |
87 | ||
88 | 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. | |
c99abb8f CM |
94 | |
95 | inode32 | |
3e5b7d8b DC |
96 | 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. | |
100 | ||
101 | 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 (*) | |
fc97bbf3 | 116 | If "nolargeio" is specified, the optimal I/O reported in |
3e5b7d8b DC |
117 | 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. | |
fc97bbf3 | 128 | |
1da177e4 | 129 | logbufs=value |
3e5b7d8b DC |
130 | 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 | |
9ed354b7 | 138 | controls the size of each buffer and so is also relevant to |
3e5b7d8b | 139 | this case. |
1da177e4 LT |
140 | |
141 | logbsize=value | |
3e5b7d8b DC |
142 | 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). | |
1da177e4 LT |
152 | |
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 | |
3e5b7d8b DC |
161 | 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. | |
1da177e4 LT |
165 | |
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 | |
3e5b7d8b DC |
175 | 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. | |
1da177e4 | 183 | |
fc97bbf3 | 184 | uquota/usrquota/uqnoenforce/quota |
1da177e4 | 185 | User disk quota accounting enabled, and limits (optionally) |
fc97bbf3 | 186 | enforced. Refer to xfs_quota(8) for further details. |
1da177e4 | 187 | |
fc97bbf3 | 188 | gquota/grpquota/gqnoenforce |
1da177e4 | 189 | Group disk quota accounting enabled and limits (optionally) |
fc97bbf3 NS |
190 | 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. | |
1da177e4 LT |
195 | |
196 | sunit=value and swidth=value | |
3e5b7d8b DC |
197 | 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. | |
1da177e4 | 212 | |
fc97bbf3 NS |
213 | 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 | ||
3e5b7d8b DC |
218 | 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 | ||
228 | Deprecated 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. | |
fc97bbf3 | 255 | |
1da177e4 LT |
256 | sysctls |
257 | ======= | |
258 | ||
259 | The following sysctls are available for the XFS filesystem: | |
260 | ||
261 | fs.xfs.stats_clear (Min: 0 Default: 0 Max: 1) | |
fc97bbf3 | 262 | Setting this to "1" clears accumulated XFS statistics |
1da177e4 | 263 | in /proc/fs/xfs/stat. It then immediately resets to "0". |
fc97bbf3 | 264 | |
1da177e4 | 265 | fs.xfs.xfssyncd_centisecs (Min: 100 Default: 3000 Max: 720000) |
3e5b7d8b DC |
266 | The interval at which the filesystem flushes metadata |
267 | out to disk and runs internal cache cleanup routines. | |
1da177e4 | 268 | |
3e5b7d8b DC |
269 | 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. | |
1da177e4 | 273 | |
3e5b7d8b DC |
274 | 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. | |
1da177e4 LT |
280 | |
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 | ||
de8bd0eb | 290 | fs.xfs.panic_mask (Min: 0 Default: 0 Max: 255) |
fc97bbf3 | 291 | Causes certain error conditions to call BUG(). Value is a bitmask; |
de8bd0eb | 292 | OR together the tags which represent errors which should cause panics: |
fc97bbf3 | 293 | |
1da177e4 LT |
294 | 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 | |
de8bd0eb | 302 | XFS_PTAG_FSBLOCK_ZERO 0x00000080 |
1da177e4 | 303 | |
fc97bbf3 | 304 | This option is intended for debugging only. |
1da177e4 LT |
305 | |
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 | |
fc97bbf3 NS |
313 | 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 | |
1da177e4 LT |
315 | is set. |
316 | ||
fc97bbf3 NS |
317 | 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 | |
1da177e4 LT |
320 | inherited by files in that directory. |
321 | ||
fc97bbf3 NS |
322 | 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 | |
1da177e4 LT |
325 | inherited by files in that directory. |
326 | ||
fc97bbf3 NS |
327 | 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 | |
1da177e4 | 330 | inherited by files in that directory. |
fc97bbf3 NS |
331 | |
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 | ||
3e5b7d8b DC |
337 | 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 | ||
fc97bbf3 NS |
342 | 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. | |
3e5b7d8b DC |
348 | |
349 | Deprecated Sysctls | |
350 | ================== | |
351 | ||
64af7a6e | 352 | None at present. |
3e5b7d8b | 353 | |
3e5b7d8b | 354 | |
64af7a6e DC |
355 | Removed Sysctls |
356 | =============== | |
3e5b7d8b | 357 | |
64af7a6e DC |
358 | Name Removed |
359 | ---- ------- | |
360 | fs.xfs.xfsbufd_centisec v3.20 | |
361 | fs.xfs.age_buffer_centisecs v3.20 |