NAME
newfs
- construct a new file system
SYNOPSIS
newfs
[-FINZ]
[-a maxcontig]
[-B byte-order]
[-b block-size]
[-d maxbsize]
[-e maxbpg]
[-f frag-size]
[-g avgfilesize]
[-h avgfpdir]
[-i bytes-per-inode]
[-m free-space]
[-n inodes]
[-O filesystem-format]
[-o optimization]
[-S sector-size]
[-s size]
[-T disk-type]
[-v volname]
[-V verbose]
special
DESCRIPTION
newfs
is used to initialize and clear file systems before first use.
Before running
newfs
the disk must be labeled using
disklabel(8).
newfs
builds a file system on the specified special device
basing its defaults on the information in the disk label.
Typically the defaults are reasonable, however
newfs
has numerous options to allow the defaults to be selectively overridden.
Options with numeric arguments may contain an optional (case-insensitive)
suffix:
- b
-
Bytes; causes no modification.
(Default)
- k
-
Kilo; multiply the argument by 1024
- m
-
Mega; multiply the argument by 1048576
- g
-
Giga; multiply the argument by 1073741824
- t
-
Tera; multiply the argument by 1099511627776
The following options define the general layout policies.
- -a maxcontig
-
This sets the obsolete maxcontig parameter.
- -B byte-order
-
Specify the metadata byte order of the file system to be created.
Valid byte orders are
`be'
and
`le'.
If no byte order is specified, the file system is created in host
byte order.
- -b block-size
-
The block size of the file system, in bytes.
It must be a power of two.
The smallest allowable size is 4096 bytes.
The default size depends upon the size of the file system:
- file system size
-
block-size
- < 20 MB
-
4 KB
- < 1024 MB
-
8 KB
- >= 1024 MB
-
16 KB
- -d maxbsize
-
Set the maximum extent size to
maxbsize.
- -e 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
tunefs(8)
for more details on how to set this option.
- -F
-
Create a file system image in
special.
The file system size needs to be specified with
``-s size''.
No attempts to use or update the disk label will be made.
- -f frag-size
-
The fragment size of the file system in bytes.
It must be a power of two ranging in value between
block-size/8
and
block-size.
The optimal
block-size:frag-size
ratio is 8:1.
Other ratios are possible, but are not recommended,
and may produce unpredictable results.
The default size depends upon the size of the file system:
- file system size
-
frag-size
- < 20 MB
-
0.5 KB
- < 1024 MB
-
1 KB
- >= 1024 MB
-
2 KB
- -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
-
Do not require that the file system type listed in the disk label is
`4.2BSD'
or
`Apple UFS'.
- -i bytes-per-inode
-
This specifies the density of inodes in the file system.
If fewer inodes are desired, a larger number should be used;
to create more inodes a smaller number should be given.
The default is to create an inode for every
(4 * frag-size)
bytes of data space:
- file system size
-
bytes-per-inode
- < 20 MB
-
2 KB
- < 1024 MB
-
4 KB
- >= 1024 MB
-
8 KB
- -m free-space
-
The percentage of space reserved from normal users; the minimum free
space threshold.
The default value used is 5%.
See
tunefs(8)
for more details on how to set this option.
- -N
-
Causes the file system parameters to be printed out
without really creating the file system.
- -n inodes
-
This specifies the number of inodes for the filesystem.
If both
-i
and
-n
are specified then
-n
takes precedence.
- -O filesystem-format
-
Select the filesystem-format
- 0
-
4.3BSD; This option is primarily used to build root file systems that can be
understood by older boot ROMs.
- 1
-
FFSv1; normal fast-filesystem (default).
- 2
-
FFSv2; enhanced fast-filesystem (suited for more than 1 Terabyte capacity,
access control lists).
To create an LFS filesystem see
newfs_lfs(8).
To create a Linux Ext2 filesystem see
newfs_ext2fs(8).
- -o optimization
-
Optimization preference; either
``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 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
tunefs(8)
for more details on how to set this option.
- -s size
-
The size of the file system in sectors.
An
`s'
suffix will be interpreted as the number of sectors (the default).
All other suffixes are interpreted as per other numeric arguments,
except that the number is converted into sectors by dividing by the
sector size (as specified by
-S secsize)
after suffix interpretation.
If no
-s size
is specified then the filesystem size defaults to that of the partition, or,
if
-F
is specified, the existing file.
If
size
is negative the specified size is subtracted from the default size
(reserving space at the end of the partition).
- -T disk-type
-
Uses information for the specified disk from
/etc/disktab
instead of trying to get the information from the disk label.
- -v volname
-
This specifies that an Apple UFS filesystem should be created
with the given volume name.
- -V verbose
-
This controls the amount of information written to stdout:
- 0
-
No output
- 1
-
Overall size and cylinder group details.
- 2
-
A progress bar (dots ending at right hand margin).
- 3
-
The first few super-block backup sector numbers are displayed before the
progress bar.
- 4
-
All the super-block backup sector numbers are displayed (no progress bar).
The default is 3.
If
-N
is specifed
newfs
stops before outputting the progress bar.
- -Z
-
Pre-zeros the file system image created with
-F.
This is necessary if the image is to be used by
vnd(4)
(which doesn't support file systems with
`holes').
The following option overrides the standard sizes for the disk geometry.
The default value is taken from the disk label.
Changing this default 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 this value from its default will make
it impossible for
fsck_ffs(8)
to find the alternative superblocks if the standard superblock is lost.
- -S sector-size
-
The size of a sector in bytes (almost never anything but 512).
Defaults to 512.
NOTES
The file system is created with
`random'
inode generation numbers to improve NFS security.
The owner and group ids of the root node of the new file system
are set to the effective uid and gid of the user initializing
the file system.
For the
newfs
command to succeed,
the disk label should first be updated such that the fstype field for the
partition is set to
`4.2BSD'
or
`Apple UFS',
unless
-F
or
-I
is used.
To create and populate a filesystem image within a file use the
makefs(8)
utility.
The partition size is found using
fstat(2)
not by inspecting the disklabel.
The block size and fragment size will be written back to the disklabel
only if the last character of
special
references the same partition as the minor device number.
that provide disk like block and character devices.
SEE ALSO
fstat(2),
disktab(5),
fs(5),
disklabel(8),
diskpart(8),
dumpfs(8),
fsck_ffs(8),
makefs(8),
mount(8),
mount_mfs(8),
newfs_ext2fs(8),
newfs_lfs(8),
newfs_msdos(8),
tunefs(8)
HISTORY
The
newfs
command appeared in
4.2BSD.