Provided by: ufsutils_8.2-3_amd64 bug

NAME

     newfs — construct a new UFS1/UFS2 file system

SYNOPSIS

     newfs [-EJNUln] [-L volname] [-O filesystem-type] [-S sector-size] [-T disktype]
           [-a maxcontig] [-b block-size] [-c blocks-per-cylinder-group] [-d max-extent-size]
           [-e maxbpg] [-f frag-size] [-g avgfilesize] [-h avgfpdir] [-i bytes] [-m free-space]
           [-o optimization] [-p partition] [-r reserved] [-s size] special

DESCRIPTION

     The newfs utility is used to initialize and clear file systems before first use.  The newfs
     utility builds a file system on the specified special file.  (We often refer to the “special
     file” as the “disk”, although the special file need not be a physical disk.  In fact, it
     need not even be special.)  Typically the defaults are reasonable, however newfs has
     numerous options to allow the defaults to be selectively overridden.

     The following options define the general layout policies:

     -E      Erase the content of the disk before making the filesystem.  The reserved area in
             front of the superblock (for bootcode) will not be erased.

             This is a relevant option for flash based storage devices that use wear levelling
             algorithms.

             NB: Erasing may take as long time as writing every sector on the disk.

     -J      Enable journaling on the new file system via gjournal.  See gjournal(8) for details.

     -L volname
             Add a volume label to the new file system.

     -N      Cause the file system parameters to be printed out without really creating the file
             system.

     -O filesystem-type
             Use 1 to specify that a UFS1 format file system be built; use 2 to specify that a
             UFS2 format file system be built.  The default format is UFS2.

     -T disktype
             For backward compatibility.

     -U      Enable soft updates on the new file system.

     -a maxcontig
             Specify the maximum number of contiguous blocks that will be laid out before forcing
             a rotational delay.  The default value is 16.  See tunefs(8) for more details on how
             to set this option.

     -b block-size
             The block size of the file system, in bytes.  It must be a power of 2.  The default
             size is 16384 bytes, and the smallest allowable size is 4096 bytes.  The optimal
             block:fragment ratio is 8:1.  Other ratios are possible, but are not recommended,
             and may produce poor results.

     -c blocks-per-cylinder-group
             The number of blocks per cylinder group in a file system.  The default is to compute
             the maximum allowed by the other parameters.  This value is dependent on a number of
             other parameters, in particular the block size and the number of bytes per inode.

     -d max-extent-size
             The file system may choose to store large files using extents.  This parameter
             specifies the largest extent size that may be used.  It is presently limited to its
             default value which is 16 times the file system blocksize.

     -e maxbpg
             Indicate 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
             tunefs(8) for more details on how to set this option.

     -f frag-size
             The fragment size of the file system in bytes.  It must be a power of two ranging in
             value between blocksize/8 and blocksize.  The default is 2048 bytes.

     -g avgfilesize
             The expected average file size for the file system.

     -h avgfpdir
             The expected average number of files per directory on the file system.

     -i bytes
             Specify the density of inodes in the file system.  The default is to create an inode
             for every (4 * frag-size) 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.  One inode is required for each distinct file, so this value effectively
             specifies the average file size on the file system.

     -l      Enable multilabel MAC on the new file system.

     -m free-space
             The percentage of space reserved from normal users; the minimum free space
             threshold.  The default value used is defined by MINFREE from <ufs/ffs/fs.h>,
             currently 8%.  See tunefs(8) for more details on how to set this option.

     -n      Do not create a .snap directory on the new file system.  The resulting file system
             will not support snapshot generation, so dump(8) in live mode and background fsck(8)
             will not function properly.  The traditional fsck(8) and offline dump(8) will work
             on the file system.  This option is intended primarily for memory or vnode-backed
             file systems that do not require dump(8) or fsck(8) support.

     -o optimization
             (space or 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.  If the value of minfree (see above) is less than 8%, the default is to
             optimize for space; if the value of minfree is greater than or equal to 8%, the
             default is to optimize for time.  See tunefs(8) for more details on how to set this
             option.

     -p partition
             The partition name (a..h) you want to use in case the underlying image is a file, so
             you don't have access to individual partitions through the filesystem.  Can also be
             used with a device, e.g.  newfs -p f /dev/da1s3 is equivalent to newfs /dev/da1s3f.

     -r reserved
             The size, in sectors, of reserved space at the end of the partition specified in
             special.  This space will not be occupied by the file system; it can be used by
             other consumers such as geom(4).  Defaults to 0.

     -s size
             The size of the file system in sectors.  This value defaults to the size of the raw
             partition specified in special less the reserved space at its end (see -r).  A size
             of 0 can also be used to choose the default value.  A valid size value cannot be
             larger than the default one, which means that the file system cannot extend into the
             reserved space.

     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
     newfs 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 fsck(8) to
     find the alternate superblocks if the standard superblock is lost.

     -S sector-size
             The size of a sector in bytes (almost never anything but 512).

EXAMPLES

           newfs /dev/ad3s1a

     Creates a new ufs file system on ad3s1a.  The newfs utility will use a block size of 16384
     bytes, a fragment size of 2048 bytes and the largest possible number of blocks per cylinders
     group.  These values tend to produce better performance for most applications than the
     historical defaults (8192 byte block size and 1024 byte fragment size).  This large fragment
     size may lead to much wasted space on file systems that contain many small files.

SEE ALSO

     fdformat(1), geom(4), disktab(5), fs(5), bsdlabel(8), camcontrol(8), dump(8), dumpfs(8),
     fsck(8), gjournal(8), mount(8), tunefs(8), gvinum(8)

     M. McKusick, W. Joy, S. Leffler, and R. Fabry, "A Fast File System for UNIX", ACM
     Transactions on Computer Systems 2, 3, pp 181-197, August 1984, (reprinted in the BSD System
     Manager's Manual).

HISTORY

     The newfs utility appeared in 4.2BSD.