.\" $OpenBSD: newfs.8,v 1.49 2006/11/14 10:28:11 otto Exp $ .\" $NetBSD: newfs.8,v 1.12 1995/03/18 14:58:41 cgd Exp $ .\" .\" Copyright (c) 1983, 1987, 1991, 1993, 1994 .\" The Regents of the University of California. All rights reserved. .\" .\" Redistribution and use in source and binary forms, with or without .\" modification, are permitted provided that the following conditions .\" are met: .\" 1. Redistributions of source code must retain the above copyright .\" notice, this list of conditions and the following disclaimer. .\" 2. Redistributions in binary form must reproduce the above copyright .\" notice, this list of conditions and the following disclaimer in the .\" documentation and/or other materials provided with the distribution. .\" 3. Neither the name of the University nor the names of its contributors .\" may be used to endorse or promote products derived from this software .\" without specific prior written permission. .\" .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE .\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF .\" SUCH DAMAGE. .\" .\" @(#)newfs.8 8.3 (Berkeley) 3/27/94 .\" .Dd March 27, 1994 .Dt NEWFS 8 .Os .Sh NAME .Nm newfs , mount_mfs .Nd construct a new file system .Sh SYNOPSIS .Nm newfs .Bk -words .Op Fl NOq .Op Fl a Ar maxcontig .Op Fl b Ar block-size .Op Fl c Ar cylinders .Op Fl d Ar rotdelay .Op Fl e Ar maxbpg .Op Fl f Ar frag-size .Op Fl g Ar avgfilesize .Op Fl h Ar avgfpdir .Op Fl i Ar bytes .Op Fl k Ar skew .Op Fl l Ar interleave .Op Fl m Ar free-space .Op Fl o Ar optimization .Op Fl p Ar sectors .Op Fl r Ar revolutions .Op Fl S Ar sector-size .Op Fl s Ar size .Op Fl t Ar fstype .Op Fl u Ar sectors .Op Fl x Ar sectors .Op Fl z Ar tracks .Ar special .Ek .Pp .Nm mount_mfs .Bk -words .Op Fl a Ar maxcontig .Op Fl b Ar block-size .Op Fl c Ar cylinders .Op Fl d Ar rotdelay .Op Fl e Ar maxbpg .Op Fl f Ar frag-size .Op Fl i Ar bytes .Op Fl m Ar free space .Op Fl o Ar options .Op Fl P Ar file .Op Fl s Ar size .Ar special node .Ek .Sh DESCRIPTION Before running .Nm or .Nm mount_mfs , the disk must be labeled using .Xr disklabel 8 . .Nm builds a file system on the specified .Ar special device, basing its defaults on the information in the disk label. Typically the defaults are reasonable, although .Nm has numerous options to allow the defaults to be selectively overridden. .Pp .Nm mount_mfs is used to build a file system in virtual memory and then mount it on a specified node. .Nm mount_mfs exits and the contents of the file system are lost when the file system is unmounted. If .Nm mount_mfs is sent a signal while running, for example during system shutdown, it will attempt to unmount its corresponding file system. The parameters to .Nm mount_mfs are the same as those to .Nm newfs . The special file is only used to read the disk label which provides a set of configuration parameters for the memory based file system. The special file is typically that of the primary swap area, since that is where the file system will be backed up when free memory gets low and the memory supporting the file system has to be paged. If the keyword .Dq swap is used instead of a special file name, default configuration parameters will be used. (This option is useful when trying to use .Nm mount_mfs on a machine without any disks.) .Pp Both .Nm and .Nm mount_mfs now have the functionality of .Xr fsirand 8 built in, so it is not necessary to run .Xr fsirand 8 manually unless you wish to re-randomize the file system (or list the inode generation numbers). .Pp The following options define the general layout policies: .Bl -tag -width Fl .It Fl a Ar maxcontig This specifies the maximum number of contiguous blocks that will be laid out before forcing a rotational delay (see the .Fl d option). The default value depends on the block size (4 for 16KB blocks, 8 for 8KB blocks, and 16 for 4KB blocks). See .Xr tunefs 8 for more details on how to set this option. .It Fl b Ar block-size The block size of the file system, in bytes. The default is 16KB. .It Fl c Ar cylinders The number of cylinders per cylinder group in a file system. The default is to use as many as fit with the other parameters given. .It Fl d Ar rotdelay This specifies the expected time (in milliseconds) to service a transfer completion interrupt and initiate a new transfer on the same disk. The default is 0 milliseconds. See .Xr tunefs 8 for more details on how to set this option. .It Fl e Ar maxbpg This indicates the maximum number of blocks any single file can allocate out of a cylinder group before it is forced to begin allocating blocks from another cylinder group. The default is about one quarter of the total blocks in a cylinder group. See .Xr tunefs 8 for more details on how to set this option. .It Fl f Ar frag-size The fragment size of the file system in bytes. The default is 2048. .It Fl g Ar avgfilesize The expected average file size for the file system in bytes. .It Fl h Ar avgfpdir The expected average number of files per directory on the file system. .It Fl i Ar bytes This specifies the density of inodes in the file system. The default is to create an inode for each 8192 bytes of data space. If fewer inodes are desired, a larger number should be used; to create more inodes a smaller number should be given. .It Fl m Ar free-space The percentage of space reserved from normal users; the minimum free space threshold. The default value used is 5%. See .Xr tunefs 8 for more details on how to set this option. .It Fl N Causes the file system parameters to be printed out without really creating the file system. .It Fl O Creates a .Bx 4.3 format file system. This option is primarily used to build root file systems that can be understood by older boot ROMs. .It Fl o Ar optimization .Ar space or .Ar time . The file system can either be instructed to try to minimize the time spent allocating blocks, or to try to minimize the space fragmentation on the disk. Unless an optimization has been specified, if the value of minfree (see above) is less than 5%, the default is to optimize for space; if the value of minfree is greater than or equal to 5%, the default is to optimize for time. See .Xr tunefs 8 for more details on how to set this option. .It Fl q Operate in quiet mode. With this option, .Nm will not print extraneous information like superblock backups. .It Fl s Ar size The size of the file system in sectors. The maximum size of a file system is 2,147,483,647 (2^31 \- 1) sectors, which is slightly less than 1TB, assuming a sector size of 512 bytes. Note however that for .Nm mount_mfs the practical limit is based on .Va datasize in .Xr login.conf 5 , and ultimately depends on the per-arch .Dv MAXDSIZ limit. .El .Pp The following options override the standard sizes for the disk geometry. Their default values are taken from the disk label. Changing these defaults is useful only when using .Nm to build a file system whose raw image will eventually be used on a different type of disk than the one on which it is initially created (for example on a write-once disk). Note that changing any of these values from their defaults will make it impossible for .Xr fsck 8 to find the alternate superblocks if the standard superblock is lost. .Bl -tag -width Fl .It Fl k Ar skew Used to describe perturbations in the media format to compensate for a slow controller. Track skew is the offset of sector 0 on track N relative to sector 0 on track N\-1 on the same cylinder. .It Fl l Ar interleave Used to describe perturbations in the media format to compensate for a slow controller. Interleave is physical sector interleave on each track, specified as the denominator of the ratio: .Dl sectors read/sectors passed over Thus an interleave of 1/1 implies contiguous layout, while 1/2 implies logical sector 0 is separated by one sector from logical sector 1. .It Fl p Ar sectors Spare sectors (bad sector replacements) are physical sectors that occupy space at the end of each track. They are not counted as part of the sectors/track .Pq Fl u since they are not available to the file system for data allocation. .It Fl r Ar revolutions The speed of the disk in revolutions per minute. .It Fl S Ar sector-size The size of a sector in bytes (almost never anything but 512). .It Fl t Ar fstype Set the file system type of which file system you wish to create. .Nm will be smart enough to run the alternate newfs_XXX program instead. .It Fl u Ar sectors The number of sectors per track available for data allocation by the file system. This does not include sectors reserved at the end of each track for bad block replacement (see the .Fl p option). .It Fl x Ar sectors Spare sectors (bad sector replacements) are physical sectors that occupy space at the end of the last track in the cylinder. They are deducted from the sectors/track .Pq Fl u of the last track of each cylinder since they are not available to the file system for data allocation. .It Fl z Ar tracks The number of tracks/cylinder available for data allocation by the file system. .El .Pp The options to the .Nm mount_mfs command are as described for the .Nm command, except for the .Fl o and .Fl P options. .Pp These options are as follows: .Bl -tag -width indent .It Fl o Ar options Options are specified with a .Fl o flag followed by a comma separated string of options. See the .Xr mount 8 man page for possible options and their meanings. .It Fl P Ar file If .Ar file is a directory, populate the created mfs file system with the contents of the directory. If .Ar file is a block device, populate the created mfs file system with the contents of the FFS file system contained on the device. .El .Pp If the .Fl P Ar file option is not used, the owner and mode of the created mfs file system will be the same as the owner and mode of the mount point. .Sh ENVIRONMENT .Bl -tag -width TMPDIR .It Ev TMPDIR Directory in which to create temporary mount points for use by .Nm mount_mfs Fl P instead of .Pa /tmp . .El .Sh SEE ALSO .Xr disktab 5 , .Xr fs 5 , .Xr disklabel 8 , .Xr dumpfs 8 , .Xr fsck 8 , .Xr fsirand 8 , .Xr growfs 8 , .Xr mount 8 , .Xr tunefs 8 .Rs .%A M. McKusick .%A W. Joy .%A S. Leffler .%A R. Fabry .%T A Fast File System for UNIX .%J ACM Transactions on Computer Systems 2 .%V 3 .%P pp 181-197 .%D August 1984 .%O (reprinted in the BSD System Manager's Manual) .Re .Sh HISTORY The .Nm command appeared in .Bx 4.2 .