1
.\" Copyright (c) 1983, 1987, 1991, 1993, 1994
2
.\" The Regents of the University of California. All rights reserved.
4
.\" Redistribution and use in source and binary forms, with or without
5
.\" modification, are permitted provided that the following conditions
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
10
.\" notice, this list of conditions and the following disclaimer in the
11
.\" documentation and/or other materials provided with the distribution.
12
.\" 4. Neither the name of the University nor the names of its contributors
13
.\" may be used to endorse or promote products derived from this software
14
.\" without specific prior written permission.
16
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
17
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
20
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28
.\" @(#)newfs.8 8.6 (Berkeley) 5/3/95
36
.Nd construct a new UFS1/UFS2 file system
41
.Op Fl O Ar filesystem-type
42
.Op Fl S Ar sector-size
45
.Op Fl b Ar block-size
46
.Op Fl c Ar blocks-per-cylinder-group
47
.Op Fl d Ar max-extent-size
50
.Op Fl g Ar avgfilesize
53
.Op Fl m Ar free-space
54
.Op Fl o Ar optimization
62
utility is used to initialize and clear file systems before first use.
65
utility builds a file system on the specified special file.
66
(We often refer to the
70
although the special file need not be a physical disk.
71
In fact, it need not even be special.)
72
Typically the defaults are reasonable, however
74
has numerous options to allow the defaults to be selectively overridden.
76
The following options define the general layout policies:
77
.Bl -tag -width indent
79
Erase the content of the disk before making the filesystem.
80
The reserved area in front of the superblock (for bootcode) will not be erased.
82
This is a relevant option for flash based storage devices that use
83
wear levelling algorithms.
85
NB: Erasing may take as long time as writing every sector on the disk.
87
Enable journaling on the new file system via gjournal.
92
Add a volume label to the new file system.
94
Cause the file system parameters to be printed out
95
without really creating the file system.
96
.It Fl O Ar filesystem-type
97
Use 1 to specify that a UFS1 format file system be built;
98
use 2 to specify that a UFS2 format file system be built.
99
The default format is UFS2.
101
For backward compatibility.
103
Enable soft updates on the new file system.
104
.It Fl a Ar maxcontig
105
Specify the maximum number of contiguous blocks that will be
106
laid out before forcing a rotational delay.
107
The default value is 16.
110
for more details on how to set this option.
111
.It Fl b Ar block-size
112
The block size of the file system, in bytes.
113
It must be a power of 2.
115
default size is 16384 bytes, and the smallest allowable size is 4096 bytes.
116
The optimal block:fragment ratio is 8:1.
117
Other ratios are possible, but are not recommended,
118
and may produce poor results.
119
.It Fl c Ar blocks-per-cylinder-group
120
The number of blocks per cylinder group in a file system.
121
The default is to compute the maximum allowed by the other parameters.
123
dependent on a number of other parameters, in particular the block size
124
and the number of bytes per inode.
125
.It Fl d Ar max-extent-size
126
The file system may choose to store large files using extents.
127
This parameter specifies the largest extent size that may be used.
128
It is presently limited to its default value which is 16 times
129
the file system blocksize.
131
Indicate the maximum number of blocks any single file can
132
allocate out of a cylinder group before it is forced to begin
133
allocating blocks from another cylinder group.
134
The default is about one quarter of the total blocks in a cylinder group.
137
for more details on how to set this option.
138
.It Fl f Ar frag-size
139
The fragment size of the file system in bytes.
140
It must be a power of two
141
ranging in value between
145
The default is 2048 bytes.
146
.It Fl g Ar avgfilesize
147
The expected average file size for the file system.
149
The expected average number of files per directory on the file system.
151
Specify the density of inodes in the file system.
152
The default is to create an inode for every
155
If fewer inodes are desired, a larger number should be used;
156
to create more inodes a smaller number should be given.
157
One inode is required for each distinct file, so this value effectively
158
specifies the average file size on the file system.
160
Enable multilabel MAC on the new file system.
161
.It Fl m Ar free-space
162
The percentage of space reserved from normal users; the minimum free
164
The default value used is
172
for more details on how to set this option.
176
directory on the new file system.
177
The resulting file system will not support snapshot generation, so
179
in live mode and background
181
will not function properly.
186
will work on the file system.
187
This option is intended primarily for memory or vnode-backed file systems that
193
.It Fl o Ar optimization
197
The file system can either be instructed to try to minimize the time spent
198
allocating blocks, or to try to minimize the space fragmentation on the disk.
199
If the value of minfree (see above) is less than 8%,
200
the default is to optimize for
202
if the value of minfree is greater than or equal to 8%,
203
the default is to optimize for
207
for more details on how to set this option.
208
.It Fl p Ar partition
209
The partition name (a..h) you want to use in case the underlying image
210
is a file, so you don't have access to individual partitions through the
212
Can also be used with a device, e.g.
220
The size, in sectors, of reserved space
221
at the end of the partition specified in
223
This space will not be occupied by the file system;
224
it can be used by other consumers such as
228
The size of the file system in sectors.
229
This value defaults to the size of the
230
raw partition specified in
234
space at its end (see
238
of 0 can also be used to choose the default value.
241
value cannot be larger than the default one,
242
which means that the file system cannot extend into the reserved space.
245
The following options override the standard sizes for the disk geometry.
246
Their default values are taken from the disk label.
247
Changing these defaults is useful only when using
249
to build a file system whose raw image will eventually be used on a
250
different type of disk than the one on which it is initially created
251
(for example on a write-once disk).
252
Note that changing any of these values from their defaults will make
255
to find the alternate superblocks if the standard superblock is lost.
256
.Bl -tag -width indent
257
.It Fl S Ar sector-size
258
The size of a sector in bytes (almost never anything but 512).
261
.Dl newfs /dev/ad3s1a
263
Creates a new ufs file system on
267
utility will use a block size of 16384 bytes, a fragment size of 2048 bytes
268
and the largest possible number of blocks per cylinders group.
269
These values tend to produce better performance for most applications
270
than the historical defaults
271
(8192 byte block size and 1024 byte fragment size).
272
This large fragment size may lead to much wasted space
273
on file systems that contain many small files.
293
.%T A Fast File System for UNIX
294
.%J ACM Transactions on Computer Systems 2
298
.%O (reprinted in the BSD System Manager's Manual)