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984263bc MD |
1 | .\" Copyright (c) 1983, 1987, 1991, 1993, 1994 |
2 | .\" The Regents of the University of California. All rights reserved. | |
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4 | .\" Redistribution and use in source and binary forms, with or without | |
5 | .\" modification, are permitted provided that the following conditions | |
6 | .\" are met: | |
7 | .\" 1. Redistributions of source code must retain the above copyright | |
8 | .\" notice, this list of conditions and the following disclaimer. | |
9 | .\" 2. Redistributions in binary form must reproduce the above copyright | |
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11 | .\" documentation and/or other materials provided with the distribution. | |
dc71b7ab | 12 | .\" 3. Neither the name of the University nor the names of its contributors |
984263bc MD |
13 | .\" may be used to endorse or promote products derived from this software |
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16 | .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND | |
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28 | .\" @(#)newfs.8 8.6 (Berkeley) 5/3/95 | |
29 | .\" $FreeBSD: src/sbin/newfs/newfs.8,v 1.26.2.15 2003/05/13 12:16:08 joerg Exp $ | |
30 | .\" | |
811c2036 | 31 | .Dd February 10, 2019 |
984263bc MD |
32 | .Dt NEWFS 8 |
33 | .Os | |
34 | .Sh NAME | |
35 | .Nm newfs , | |
36 | .Nm mount_mfs | |
8895c5fa | 37 | .Nd construct a new UFS file system |
984263bc MD |
38 | .Sh SYNOPSIS |
39 | .Nm | |
b796e0dd | 40 | .Op Fl L Ar volname |
7b8c2c90 | 41 | .Op Fl NCEOU |
984263bc MD |
42 | .Op Fl S Ar sector-size |
43 | .Op Fl T Ar disktype | |
44 | .Op Fl a Ar maxcontig | |
45 | .Op Fl b Ar block-size | |
46 | .Op Fl c Ar cylinders | |
47 | .Op Fl d Ar rotdelay | |
48 | .Op Fl e Ar maxbpg | |
49 | .Op Fl f Ar frag-size | |
50 | .Op Fl g Ar avgfilesize | |
51 | .Op Fl h Ar avfpdir | |
52 | .Op Fl i Ar bytes | |
53 | .Op Fl k Ar skew | |
54 | .Op Fl l Ar interleave | |
55 | .Op Fl m Ar free space | |
56 | .Op Fl n Ar rotational positions | |
57 | .Op Fl o Ar optimization | |
58 | .Op Fl p Ar sectors | |
59 | .Op Fl r Ar revolutions | |
60 | .Op Fl s Ar size | |
61 | .Op Fl t Ar tracks | |
62 | .Op Fl u Ar sectors | |
63 | .Op Fl v | |
64 | .Op Fl x Ar sectors | |
65 | .Ar special | |
66 | .Nm mount_mfs | |
67 | .Op Fl NU | |
68 | .Op Fl F Ar file | |
69 | .Op Fl T Ar disktype | |
70 | .Op Fl a Ar maxcontig | |
71 | .Op Fl b Ar block-size | |
72 | .Op Fl c Ar cylinders | |
73 | .Op Fl d Ar rotdelay | |
74 | .Op Fl e Ar maxbpg | |
75 | .Op Fl f Ar frag-size | |
76 | .Op Fl i Ar bytes | |
77 | .Op Fl m Ar free space | |
78 | .Op Fl n Ar rotational positions | |
79 | .Op Fl o Ar options | |
80 | .Op Fl s Ar size | |
81 | .Op Fl v | |
82 | .Ar special node | |
83 | .Sh DESCRIPTION | |
84 | .Nm Newfs | |
85 | is used to initialize and clear filesystems before first use. | |
86 | Before running | |
87 | .Nm | |
88 | or | |
89 | .Nm mount_mfs , | |
90 | the disk must be labeled using | |
91 | .Xr disklabel 8 . | |
92 | .Nm Newfs | |
93 | builds a file system on the specified special file. | |
94 | (We often refer to the | |
95 | .Dq special file | |
96 | as the | |
97 | .Dq disk , | |
98 | although the special file need not be a physical disk. | |
99 | In fact, it need not even be special.) | |
100 | Typically the defaults are reasonable, however | |
101 | .Nm | |
102 | has numerous options to allow the defaults to be selectively overridden. | |
103 | .Pp | |
104 | .Nm Mount_mfs | |
105 | is used to build a file system in virtual memory and then mount it | |
106 | on a specified node. | |
107 | .Nm Mount_mfs | |
108 | exits and the contents of the file system are lost | |
109 | when the file system is unmounted. | |
110 | If | |
111 | .Nm mount_mfs | |
112 | is sent a signal while running, | |
113 | for example during system shutdown, | |
114 | it will attempt to unmount its | |
115 | corresponding file system. | |
116 | The parameters to | |
117 | .Nm mount_mfs | |
118 | are the same as those to | |
119 | .Nm . | |
120 | If the | |
121 | .Fl T | |
122 | flag is specified (see below), the special file is unused. | |
123 | Otherwise, it is only used to read the disk label which provides | |
124 | a set of configuration parameters for the memory based file system. | |
125 | The special file is typically that of the primary swap area, | |
126 | since that is where the file system will be backed up when | |
127 | free memory gets low and the memory supporting | |
128 | the file system has to be paged. | |
129 | .Pp | |
e4c9c0c8 MD |
130 | .Nm mount_mfs |
131 | creates the raw character device | |
132 | .Pa /dev/mfs<PID> | |
133 | to represent the backing store while the mount is active. This device may | |
134 | be read but not written and allows swap-based MFS filesystems to be dumped | |
135 | if desired. | |
136 | .Pp | |
984263bc MD |
137 | The following options define the general layout policies: |
138 | .Bl -tag -width indent | |
139 | .It Fl T Ar disktype | |
140 | For backward compatibility and for | |
141 | .Nm mount_mfs . | |
7b8c2c90 SW |
142 | .It Fl E |
143 | Use TRIM to erase the device's data before creating the file system. | |
144 | The underlying device must have the TRIM sysctl enabled. | |
145 | Only devices that support TRIM will have such a sysctl option | |
146 | .Va ( kern.cam.da.X.trim_enabled ) . | |
984263bc MD |
147 | .It Fl F Ar file |
148 | .Nm Mount_mfs | |
149 | will use this file for the image of the filesystem. When | |
150 | .Nm mount_mfs | |
151 | exits, this file will be left behind. | |
65087744 MD |
152 | .It Fl C |
153 | Tell | |
154 | .Nm Mount_mfs | |
155 | to copy the underlying filesystem into the MFS mount being created | |
156 | over it. | |
b796e0dd AH |
157 | .It Fl L Ar volname |
158 | Add a volume label to the new file system. | |
984263bc MD |
159 | .It Fl N |
160 | Cause the file system parameters to be printed out | |
161 | without really creating the file system. | |
162 | .It Fl O | |
163 | Create a | |
164 | .Bx 4.3 | |
165 | format filesystem. | |
166 | This options is primarily used to build root filesystems | |
167 | that can be understood by older boot ROMs. | |
168 | .It Fl T | |
169 | Use information for the specified disk from | |
170 | .Pa /etc/disktab | |
41e59acb MD |
171 | instead of trying to get geometry information from the |
172 | storage device. | |
984263bc MD |
173 | .It Fl U |
174 | Enables soft updates on the new filesystem. | |
175 | .It Fl a Ar maxcontig | |
176 | Specify the maximum number of contiguous blocks that will be | |
177 | laid out before forcing a rotational delay (see the | |
178 | .Fl d | |
179 | option). | |
180 | The default value is 1. | |
181 | See | |
182 | .Xr tunefs 8 | |
183 | for more details on how to set this option. | |
184 | .It Fl b Ar block-size | |
185 | The block size of the file system, in bytes. It must be a power of 2. The | |
186 | default size is 16384 bytes, and the smallest allowable size is 4096 bytes. | |
187 | The optimal block:fragment ratio is 8:1. | |
188 | Other ratios are possible, but are not recommended, | |
189 | and may produce unpredictable results. | |
190 | .It Fl c Ar #cylinders/group | |
191 | The number of cylinders per cylinder group in a file system. The default | |
192 | is to compute the maximum allowed by the other parameters. This value is | |
193 | dependent on a number of other parameters, in particular the block size | |
194 | and the number of bytes per inode. | |
195 | .It Fl d Ar rotdelay | |
196 | This parameter once specified the minimum time in milliseconds required to | |
197 | initiate another disk transfer on the same cylinder. It was used in determining | |
198 | the rotationally optimal layout for disk blocks within a file. Modern disks | |
199 | with read/write-behind achieve higher performance with this feature disabled, so | |
200 | this value should be left at the default value of 0 milliseconds. See | |
201 | .Xr tunefs 8 | |
202 | for more details on how to set this option. | |
203 | .It Fl e Ar maxbpg | |
204 | Indicate the maximum number of blocks any single file can | |
205 | allocate out of a cylinder group before it is forced to begin | |
206 | allocating blocks from another cylinder group. | |
207 | The default is about one quarter of the total blocks in a cylinder group. | |
208 | See | |
209 | .Xr tunefs 8 | |
210 | for more details on how to set this option. | |
211 | .It Fl f Ar frag-size | |
212 | The fragment size of the file system in bytes. It must be a power of two | |
213 | ranging in value between | |
214 | .Ar blocksize Ns /8 | |
215 | and | |
216 | .Ar blocksize . | |
217 | The default is 2048 bytes. | |
218 | .It Fl g Ar avgfilesize | |
219 | The expected average file size for the file system. | |
220 | .It Fl h Ar avgfpdir | |
221 | The expected average number of files per directory on the file system. | |
222 | .It Fl i Ar number of bytes per inode | |
223 | Specify the density of inodes in the file system. | |
224 | The default is to create an inode for every | |
225 | .Pq 4 * Ar frag-size | |
226 | bytes of data space. | |
227 | If fewer inodes are desired, a larger number should be used; | |
228 | to create more inodes a smaller number should be given. | |
229 | One inode is required for each distinct file, so this value effectively | |
230 | specifies the average file size on the file system. | |
231 | .It Fl m Ar free space \&% | |
232 | The percentage of space reserved from normal users; the minimum free | |
233 | space threshold. | |
234 | The default value used is | |
235 | defined by | |
236 | .Dv MINFREE | |
237 | from | |
95a9b861 | 238 | .In vfs/ufs/fs.h , |
984263bc MD |
239 | currently 8%. |
240 | See | |
241 | .Xr tunefs 8 | |
242 | for more details on how to set this option. | |
243 | .It Fl n Ar number of distinguished rotational positions | |
167c1ad2 SW |
244 | .Xr UFS 5 |
245 | has the ability to keep track of the availability of blocks at different | |
984263bc MD |
246 | rotational positions, so that it could lay out the data to be picked up with |
247 | minimum rotational latency. This parameter specifies the default number of | |
248 | rotational positions to distinguish. | |
249 | .Pp | |
250 | Nowadays this value should be set to 1 (which essentially disables the | |
251 | rotational position table) because modern drives with read-ahead and | |
252 | write-behind do better without the rotational position table. | |
253 | .It Fl o Ar optimization\ preference | |
8895c5fa | 254 | .Pq Cm space No or Cm time . |
984263bc MD |
255 | The file system can either be instructed to try to minimize the time spent |
256 | allocating blocks, or to try to minimize the space fragmentation on the disk. | |
257 | If the value of minfree (see above) is less than 8%, | |
258 | the default is to optimize for | |
8895c5fa | 259 | .Cm space ; |
984263bc MD |
260 | if the value of minfree is greater than or equal to 8%, |
261 | the default is to optimize for | |
8895c5fa | 262 | .Cm time . |
984263bc MD |
263 | See |
264 | .Xr tunefs 8 | |
265 | for more details on how to set this option. | |
266 | .It Fl s Ar size | |
267 | The size of the file system in sectors. This value defaults to the size of the | |
268 | raw partition specified in | |
269 | .Ar special | |
270 | (in other words, | |
271 | .Nm | |
272 | will use the entire partition for the file system). | |
273 | .It Fl v | |
274 | Specify that the disk does not contain any partitions, and that | |
275 | .Nm | |
276 | should build a file system on the whole disk. | |
277 | This option is useful for synthetic disks such as | |
278 | .Nm vinum . | |
41e59acb MD |
279 | It may also be used to allow |
280 | .Nm | |
281 | to operate on regular files. | |
282 | When operating on a regular file, | |
283 | .Nm | |
284 | will synthesize a reasonable geometry for the filesystem. | |
984263bc MD |
285 | .El |
286 | .Pp | |
287 | The following options override the standard sizes for the disk geometry. | |
288 | Their default values are taken from the disk label. | |
289 | Changing these defaults is useful only when using | |
290 | .Nm | |
291 | to build a file system whose raw image will eventually be used on a | |
292 | different type of disk than the one on which it is initially created | |
293 | (for example on a write-once disk). | |
294 | Note that changing any of these values from their defaults will make | |
295 | it impossible for | |
296 | .Xr fsck 8 | |
297 | to find the alternate superblocks if the standard superblock is lost. | |
298 | .Bl -tag -width indent | |
299 | .It Fl S Ar sector-size | |
300 | The size of a sector in bytes (almost never anything but 512). | |
301 | .It Fl k Ar sector \&0 skew , per track | |
302 | Used to describe perturbations in the media format to compensate for | |
303 | a slow controller. | |
304 | Track skew is the offset of sector 0 on track N relative to sector 0 | |
305 | on track N-1 on the same cylinder. | |
306 | This option is of historical importance only; modern controllers are always fast | |
307 | enough to handle operations back-to-back. | |
308 | .It Fl l Ar hardware sector interleave | |
309 | Used to describe perturbations in the media format to compensate for | |
310 | a slow controller. | |
311 | Interleave is physical sector interleave on each track, | |
312 | specified as the denominator of the ratio: | |
313 | .Dl sectors read/sectors passed over | |
314 | Thus an interleave of 1/1 implies contiguous layout, while 1/2 implies | |
315 | logical sector 0 is separated by one sector from logical sector 1. | |
316 | This option is of historical importance only; the physical sector layout of | |
317 | modern disks is not visible from outside. | |
318 | .It Fl p Ar spare sectors per track | |
319 | Spare sectors (bad sector replacements) are physical sectors that occupy | |
320 | space at the end of each track. | |
321 | They are not counted as part of the sectors/track | |
322 | .Pq Fl u | |
323 | since they are not available to the file system for data allocation. | |
324 | This option is of historical importance only. Modern disks perform their own | |
325 | bad sector allocation. | |
326 | .It Fl r Ar revolutions/minute | |
327 | The speed of the disk in revolutions per minute. This value is no longer of | |
328 | interest, since all the parameters which depend on it are usually disabled. | |
329 | .It Fl t Ar #tracks/cylinder | |
330 | The number of tracks/cylinder available for data allocation by the file | |
331 | system. | |
332 | The default is 1. | |
41e59acb | 333 | If zero is specified, the value from the device geometry will be used. |
984263bc MD |
334 | .It Fl u Ar sectors/track |
335 | The number of sectors per track available for data allocation by the file | |
336 | system. | |
337 | The default is 4096. | |
41e59acb | 338 | If zero is specified, the value from the device geometry will be used. |
984263bc MD |
339 | This does not include sectors reserved at the end of each track for bad |
340 | block replacement (see the | |
341 | .Fl p | |
342 | option). | |
343 | .It Fl x Ar spare sectors per cylinder | |
344 | Spare sectors (bad sector replacements) are physical sectors that occupy | |
345 | space at the end of the last track in the cylinder. | |
346 | They are deducted from the sectors/track | |
347 | .Pq Fl u | |
348 | of the last track of each cylinder since they are not available to the file | |
349 | system for data allocation. | |
350 | This option is of historical importance only. Modern disks perform their own | |
351 | bad sector allocation. | |
352 | .El | |
353 | .Pp | |
354 | The options to the | |
355 | .Nm mount_mfs | |
356 | command are as described for the | |
357 | .Nm | |
358 | command, except for the | |
359 | .Fl o | |
360 | option. | |
361 | .Pp | |
362 | That option is as follows: | |
363 | .Bl -tag -width indent | |
364 | .It Fl o | |
365 | Options are specified with a | |
366 | .Fl o | |
367 | flag followed by a comma separated string of options. | |
368 | See the | |
369 | .Xr mount 8 | |
370 | man page for possible options and their meanings. | |
371 | .El | |
372 | .Sh EXAMPLES | |
373 | .Dl newfs /dev/ad3s1a | |
374 | .Pp | |
167c1ad2 | 375 | Creates a new |
745e5aed | 376 | .Xr UFS 5 |
167c1ad2 | 377 | file system on |
984263bc MD |
378 | .Pa ad3s1a . |
379 | .Nm | |
380 | will use a block size of 16384 bytes, a fragment size of 2048 bytes | |
381 | and the largest possible number of cylinders per group. | |
382 | These values tend to produce better performance for most applications | |
383 | than the historical defaults | |
384 | (8192 byte block size and 1024 byte fragment size). | |
385 | This large fragment size | |
386 | may lead to large amounts of wasted space | |
387 | on filesystems that contain a large number of small files. | |
388 | .Pp | |
389 | .Dl mount_mfs -s 131072 -o nosuid,nodev,nosymfollow /dev/da0s1b /tmp | |
390 | .Pp | |
391 | Mount a 64 MB large memory file system on | |
392 | .Pa /tmp , | |
393 | with | |
394 | .Xr mount 8 | |
395 | options | |
8895c5fa TN |
396 | .Cm nosuid , |
397 | .Cm nodev , | |
984263bc | 398 | and |
8895c5fa | 399 | .Cm nosymfollow . |
984263bc MD |
400 | .Sh SEE ALSO |
401 | .Xr fdformat 1 , | |
402 | .Xr disktab 5 , | |
403 | .Xr fs 5 , | |
dae741e3 | 404 | .Xr UFS 5 , |
984263bc MD |
405 | .Xr camcontrol 8 , |
406 | .Xr disklabel 8 , | |
984263bc MD |
407 | .Xr dumpfs 8 , |
408 | .Xr fsck 8 , | |
811c2036 | 409 | .Xr makefs 8 , |
984263bc MD |
410 | .Xr mount 8 , |
411 | .Xr tunefs 8 , | |
412 | .Xr vinum 8 | |
413 | .Rs | |
414 | .%A M. McKusick | |
415 | .%A W. Joy | |
416 | .%A S. Leffler | |
417 | .%A R. Fabry | |
418 | .%T A Fast File System for UNIX | |
419 | .%J ACM Transactions on Computer Systems 2 | |
420 | .%V 3 | |
421 | .%P pp 181-197 | |
422 | .%D August 1984 | |
423 | .%O (reprinted in the BSD System Manager's Manual) | |
424 | .Re | |
425 | .Sh HISTORY | |
426 | The | |
0b674f74 | 427 | .Nm newfs |
984263bc MD |
428 | command appeared in |
429 | .Bx 4.2 . | |
0b674f74 SW |
430 | The |
431 | .Nm mount_mfs | |
432 | command appeared in | |
433 | .Bx 4.4 . |