newfs
—
construct a new file system
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 |
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
.
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.
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.
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.
The newfs
command appeared in
4.2BSD.