NEWFS(8) | System Manager's Manual | NEWFS(8) |
newfs
, mount_mfs
— construct a new file system
newfs |
[-Nq ]
[-b block-size]
[-c fragments-per-cylinder-group]
[-e maxbpg]
[-f frag-size]
[-g avgfilesize]
[-h avgfpdir]
[-i bytes]
[-m free-space]
[-O filesystem-format]
[-o optimization]
[-S sector-size]
[-s size]
[-T disktype]
[-t fstype] special |
mount_mfs |
[-b block-size]
[-c fragments-per-cylinder-group]
[-e maxbpg]
[-f frag-size]
[-i bytes]
[-m free-space]
[-o options]
[-P file]
[-s size] special
node |
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, although
newfs
has numerous options to allow the defaults to
be selectively overridden.
The special file should be a raw device, for example /dev/rsd0a; if a relative path like sd0a is specified, the corresponding raw device is used.
mount_mfs
is used to build a file system
in virtual memory and then mount it on a specified node.
mount_mfs
exits and the contents of the file system
are lost when the file system is unmounted. If
mount_mfs
is sent a signal while running, for
example during system shutdown, it will attempt to unmount its corresponding
file system. The parameters to mount_mfs
are the
same as those to newfs
. The special file is only
used to read the disk label which provides a set of configuration parameters
for the memory based file system. The special file is typically that of the
primary swap area, since that is where the file system will be backed up
when free memory gets low and the memory supporting the file system has to
be paged. If the keyword “swap” is used instead of a special
file name, default configuration parameters will be used. (This option is
useful when trying to use mount_mfs
on a machine
without any disks.)
Both newfs
and
mount_mfs
now have the functionality of
fsirand(8) built in, so it
is not necessary to run
fsirand(8) manually unless
you wish to re-randomize the file system (or list the inode generation
numbers).
The options to newfs
are as follows:
-b
block-size-c
fragments-per-cylinder-group-e
maxbpg-f
frag-size-g
avgfilesize-h
avgfpdir-i
bytes-m
free-space-N
-O
filesystem-format-o
optimization-q
newfs
will not print extraneous information like superblock backups.-S
sector-sizenewfs
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 from its default will make it impossible for
fsck(8) to find the alternate
superblocks automatically if the standard superblock is lost.-s
size-S
).
Alternatively size may instead use a multiplier, as
documented in
scan_scaled(3), to
specify size in bytes; in this case size is rounded
up to the next sector boundary. The maximum size of an FFS file system is
2,147,483,647 (2^31 - 1) of 512-byte blocks, slightly less than 1 TB. FFS2
file systems can be as large as 64 PB. Note however that for
mount_mfs
the practical limit is based on
datasize in
login.conf(5), and
ultimately depends on the per-arch MAXDSIZ
limit.-T
disktype-t
fstypenewfs
will be smart enough to run the alternate
newfs_XXX program instead.The options to mount_mfs
are as described
for newfs
, except for the -o
and -P
options.
Those options are as follows:
-o
options-o
flag followed by a
comma separated string of options. See the
mount(8) man page for
possible options and their meanings.-P
fileIf the -P
file
option is not used, the owner and mode of the created mfs file system will
be the same as the owner and mode of the mount point.
COLUMNS
newfs
defaults to the terminal
width, or 80 columns if the output is not a terminal.disktab(5), fs(5), disklabel(8), dumpfs(8), fsck(8), fsirand(8), growfs(8), mount(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, M. Karels, and K. Bostic, A Pageable Memory Based Filesystem, USENIX Summer Conference Proceedings, 1990.
The newfs
command appeared in
4.2BSD.
March 17, 2016 | OpenBSD-6.1 |