1.\" Copyright (c) 1983, 1987, 1991, 1993, 1994 2.\" The Regents of the University of California. All rights reserved. 3.\" 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 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. All advertising materials mentioning features or use of this software 13.\" must display the following acknowledgement: 14.\" This product includes software developed by the University of 15.\" California, Berkeley and its contributors. 16.\" 4. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" @(#)newfs.8 8.6 (Berkeley) 5/3/95 33.\" $FreeBSD$ 34.\" 35.Dd May 29, 2001 36.Dt NEWFS 8 37.Os 38.Sh NAME 39.Nm newfs , 40.Nd construct a new file system 41.Sh SYNOPSIS 42.Nm 43.Op Fl NOU 44.Op Fl S Ar sector-size 45.Op Fl T Ar disktype 46.Op Fl a Ar maxcontig 47.Op Fl b Ar block-size 48.Op Fl c Ar cylinders 49.Op Fl d Ar rotdelay 50.Op Fl e Ar maxbpg 51.Op Fl f Ar frag-size 52.Op Fl g Ar avgfilesize 53.Op Fl h Ar avfpdir 54.Op Fl i Ar bytes 55.Op Fl k Ar skew 56.Op Fl l Ar interleave 57.Op Fl m Ar free space 58.Op Fl n Ar rotational positions 59.Op Fl o Ar optimization 60.Op Fl p Ar sectors 61.Op Fl r Ar revolutions 62.Op Fl s Ar size 63.Op Fl t Ar tracks 64.Op Fl u Ar sectors 65.Op Fl v 66.Op Fl x Ar sectors 67.Ar special 68.Sh DESCRIPTION 69.Nm Newfs 70is used to initialize and clear filesystems before first use. 71Before running 72.Nm 73the disk must be labeled using 74.Xr disklabel 8 . 75.Nm Newfs 76builds a file system on the specified special file. 77(We often refer to the 78.Dq special file 79as the 80.Dq disk , 81although the special file need not be a physical disk. 82In fact, it need not even be special.) 83Typically the defaults are reasonable, however 84.Nm 85has numerous options to allow the defaults to be selectively overridden. 86.Pp 87The following options define the general layout policies: 88.Bl -tag -width indent 89.It Fl T Ar disktype 90For backward compatibility. 91.It Fl N 92Cause the file system parameters to be printed out 93without really creating the file system. 94.It Fl O 95Create a 96.Bx 4.3 97format filesystem. 98This options is primarily used to build root filesystems 99that can be understood by older boot ROMs. 100.It Fl U 101Enables soft updates on the new filesystem. 102.It Fl a Ar maxcontig 103Specify the maximum number of contiguous blocks that will be 104laid out before forcing a rotational delay (see the 105.Fl d 106option). 107The default value is 1. 108See 109.Xr tunefs 8 110for more details on how to set this option. 111.It Fl b Ar block-size 112The block size of the file system, in bytes. It must be a power of 2. The 113default size is 8192 bytes, and the smallest allowable size is 4096 bytes. 114.It Fl c Ar #cylinders/group 115The number of cylinders per cylinder group in a file system. The default value 116is 22. The maximum value is dependent on a number of other parameters, in 117particular the block size. The best way to find the maximum value for a 118specific file system is to attempt to specify a value which is far too large: 119.Nm 120will print out the maximum value. 121.It Fl d Ar rotdelay 122This parameter once specified the minimum time in milliseconds required to 123initiate another disk transfer on the same cylinder. It was used in determining 124the rotationally optimal layout for disk blocks within a file. Modern disks 125with read/write-behind achieve higher performance with this feature disabled, so 126this value should be left at the default value of 0 milliseconds. See 127.Xr tunefs 8 128for more details on how to set this option. 129.It Fl e Ar maxbpg 130Indicate the maximum number of blocks any single file can 131allocate out of a cylinder group before it is forced to begin 132allocating blocks from another cylinder group. 133The default is about one quarter of the total blocks in a cylinder group. 134See 135.Xr tunefs 8 136for more details on how to set this option. 137.It Fl f Ar frag-size 138The fragment size of the file system in bytes. It must be a power of two 139ranging in value between 140.Ar blocksize Ns /8 141and 142.Ar blocksize . 143The default is 1024 bytes. 144.It Fl g Ar avgfilesize 145The expected average file size for the file system. 146.It Fl h Ar avgfpdir 147The expected average number of files per directory on the file system. 148.It Fl i Ar number of bytes per inode 149Specify the density of inodes in the file system. 150The default is to create an inode for every 151.Pq 4 * Ar frag-size 152bytes of data space. 153If fewer inodes are desired, a larger number should be used; 154to create more inodes a smaller number should be given. 155One inode is required for each distinct file, so this value effectively 156specifies the average file size on the file system. 157.It Fl m Ar free space \&% 158The percentage of space reserved from normal users; the minimum free 159space threshold. 160The default value used is 161defined by 162.Dv MINFREE 163from 164.Aq Pa ufs/ffs/fs.h , 165currently 8%. 166See 167.Xr tunefs 8 168for more details on how to set this option. 169.It Fl n Ar number of distinguished rotational positions 170UFS has the ability to keep track of the availability of blocks at different 171rotational positions, so that it could lay out the data to be picked up with 172minimum rotational latency. This parameter specifies the default number of 173rotational positions to distinguish. 174.Pp 175Nowadays this value should be set to 1 (which essentially disables the 176rotational position table) because modern drives with read-ahead and 177write-behind do better without the rotational position table. 178.It Fl o Ar optimization\ preference 179.Pq Ar space No or Ar time . 180The file system can either be instructed to try to minimize the time spent 181allocating blocks, or to try to minimize the space fragmentation on the disk. 182If the value of minfree (see above) is less than 8%, 183the default is to optimize for 184.Ar space ; 185if the value of minfree is greater than or equal to 8%, 186the default is to optimize for 187.Ar time . 188See 189.Xr tunefs 8 190for more details on how to set this option. 191.It Fl s Ar size 192The size of the file system in sectors. This value defaults to the size of the 193raw partition specified in 194.Ar special 195(in other words, 196.Nm 197will use the entire partition for the file system). 198.It Fl v 199Specify that the disk does not contain any partitions, and that 200.Nm 201should build a file system on the whole disk. 202This option is useful for synthetic disks such as 203.Nm vinum . 204.El 205.Pp 206The following options override the standard sizes for the disk geometry. 207Their default values are taken from the disk label. 208Changing these defaults is useful only when using 209.Nm 210to build a file system whose raw image will eventually be used on a 211different type of disk than the one on which it is initially created 212(for example on a write-once disk). 213Note that changing any of these values from their defaults will make 214it impossible for 215.Xr fsck 8 216to find the alternate superblocks if the standard superblock is lost. 217.Bl -tag -width indent 218.It Fl S Ar sector-size 219The size of a sector in bytes (almost never anything but 512). 220.It Fl k Ar sector \&0 skew , per track 221Used to describe perturbations in the media format to compensate for 222a slow controller. 223Track skew is the offset of sector 0 on track N relative to sector 0 224on track N-1 on the same cylinder. 225This option is of historical importance only; modern controllers are always fast 226enough to handle operations back-to-back. 227.It Fl l Ar hardware sector interleave 228Used to describe perturbations in the media format to compensate for 229a slow controller. 230Interleave is physical sector interleave on each track, 231specified as the denominator of the ratio: 232.Dl sectors read/sectors passed over 233Thus an interleave of 1/1 implies contiguous layout, while 1/2 implies 234logical sector 0 is separated by one sector from logical sector 1. 235This option is of historical importance only; the physical sector layout of 236modern disks is not visible from outside. 237.It Fl p Ar spare sectors per track 238Spare sectors (bad sector replacements) are physical sectors that occupy 239space at the end of each track. 240They are not counted as part of the sectors/track 241.Pq Fl u 242since they are not available to the file system for data allocation. 243This option is of historical importance only. Modern disks perform their own 244bad sector allocation. 245.It Fl r Ar revolutions/minute 246The speed of the disk in revolutions per minute. This value is no longer of 247interest, since all the parameters which depend on it are usually disabled. 248.It Fl t Ar #tracks/cylinder 249The number of tracks/cylinder available for data allocation by the file 250system. 251The default is 1. 252If zero is specified, the value from the disklabel will be used. 253.It Fl u Ar sectors/track 254The number of sectors per track available for data allocation by the file 255system. 256The default is 4096. 257If zero is specified, the value from the disklabel will be used. 258This does not include sectors reserved at the end of each track for bad 259block replacement (see the 260.Fl p 261option). 262.It Fl x Ar spare sectors per cylinder 263Spare sectors (bad sector replacements) are physical sectors that occupy 264space at the end of the last track in the cylinder. 265They are deducted from the sectors/track 266.Pq Fl u 267of the last track of each cylinder since they are not available to the file 268system for data allocation. 269This option is of historical importance only. Modern disks perform their own 270bad sector allocation. 271.El 272.Sh EXAMPLES 273.Dl newfs -b 16384 -f 4096 -c 100 /dev/ad3s1a 274.Pp 275Creates a new ufs file system on 276.Pa ad3s1a . 277.Nm 278will use a block size of 16384 bytes, a fragement size of 4096 bytes 279and have 100 cylinders per cylinder group rather than the defaults. 280These values are tend to produce better performance than the defaults 281for file systems larger than about 5 gigabytes. 282.Sh SEE ALSO 283.Xr fdformat 1 , 284.Xr disktab 5 , 285.Xr fs 5 , 286.Xr camcontrol 8 , 287.Xr disklabel 8 , 288.Xr diskpart 8 , 289.Xr dumpfs 8 , 290.Xr fsck 8 , 291.Xr mount 8 , 292.Xr tunefs 8 , 293.Xr vinum 8 294.Rs 295.%A M. McKusick 296.%A W. Joy 297.%A S. Leffler 298.%A R. Fabry 299.%T A Fast File System for UNIX 300.%J ACM Transactions on Computer Systems 2 301.%V 3 302.%P pp 181-197 303.%D August 1984 304.%O (reprinted in the BSD System Manager's Manual) 305.Re 306.Sh HISTORY 307The 308.Nm 309command appeared in 310.Bx 4.2 . 311