NAME
newfs —
construct a new file
system
SYNOPSIS
newfs |
[-FGINZ]
[-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]
[-q quota]
[-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
- < 1000 MB
- 8 KB
- < 128 GB
- 16 KB
- >= 128 GB
- 32 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
- < 1000 MB
- 1 KB
- < 128 GB
- 2 KB
- >= 128 GB
- 4 KB
-
-
- -G
- Treat garbage parameters as non-fatal. Using this option
may result in a file system which causes a kernel panic and should only be
used for testing.
-
-
- -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
- < 1000 MB
- 4 KB
- < 128 GB
- 8 KB
- >= 128 GB
- 16 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. This generates
an FFSv1 file system with level 1 format.
- 1
- FFSv1; normal Fast File System, level 4 format. Also
known as ‘FFS’, ‘UFS’, or ‘UFS1’.
This is the default.
- 2
- FFSv2; enhanced Fast File System, suited for more than
1 Terabyte capacity. This is also known as ‘UFS2’.
See fsck_ffs(8) for more
information about format levels.
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.
-
-
- -q
quota
- enable a quota. quota can be one of
user
or group
to enable
the specified quota type. Multiple -q can be used to
enable all types at once.
-
-
- -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
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 specified
newfs stops before outputting the progress bar.
-
-
- -v
volname
- This specifies that an Apple UFS filesystem should be
created with the given volume name.
-
-
- -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
disk label. The block size and fragment size will be written back to the disk
label only if the last character of
special references
the same partition as the minor device number.
Unless
-F is specified,
special must be
a raw device. This means that for example
wd0a or
/dev/rwd0a must be specified instead of
/dev/wd0a.
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)
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).
M. McKusick,
Enhancements to the fast filesystem to support
multi-terabyte storage systems, Proceedings of the BSD
Conference 2003, pp 79-90,
September 2003.
HISTORY
The
newfs command appeared in
4.2BSD.