Skip site navigation (1)Skip section navigation (2)

FreeBSD Manual Pages


home | help
NEWFS(8)                FreeBSD System Manager's Manual               NEWFS(8)

     newfs -- construct a new UFS1/UFS2 file system

     newfs [-NUln] [-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] [-s size] special

     The newfs utility is used to initialize and clear file systems before
     first use.  Before running newfs the disk must be labeled using
     bsdlabel(8).  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 over-

     The following options define the general layout policies:

     -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 allow-
             able 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 parame-
             ters.  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 allo-
             cate out of a cylinder group before it is forced to begin allo-
             cating 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

     -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 mini-
             mize the space fragmentation on the disk.  If the value of min-
             free (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.

     -s size
             The size of the file system in sectors.  This value defaults to
             the size of the raw partition specified in special (in other
             words, newfs will use the entire partition for the file system).

     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 impos-
     sible 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).

           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 pro-
     duce 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.

     fdformat(1), disktab(5), fs(5), bsdlabel(8), camcontrol(8), dump(8),
     dumpfs(8), fsck(8), mount(8), tunefs(8), vinum(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).

     The newfs utility appeared in 4.2BSD.

FreeBSD 6.2                    January 21, 2005                    FreeBSD 6.2


Want to link to this manual page? Use this URL:

home | help