mount_mfs, mdmfs(8) | configure and mount an in-memory file system using the md 4 driver or the tmpfs 5 filesystem |
mdmfs, mount_mfs(8) | configure and mount an in-memory file system using the md 4 driver or the tmpfs 5 filesystem |
MDMFS(8) | MidnightBSD System Manager's Manual | MDMFS(8) |
mdmfs
, mount_mfs
— configure and mount an in-memory file system using
the md(4) driver or the
tmpfs(5)
filesystem
mdmfs |
[-DLlMNnPStTUX ] [-a
maxcontig] [-b
block-size] [-c
blocks-per-cylinder-group]
[-d max-extent-size]
[-E path-mdconfig]
[-e maxbpg]
[-F file]
[-f frag-size]
[-i bytes]
[-k skel]
[-m percent-free]
[-O optimization]
[-o mount-options]
[-p permissions]
[-s size]
[-T fstype]
[-v version]
[-w
user:group]
md-device mount-point |
The mdmfs
utility is designed to be a
work-alike and look-alike of the deprecated
mount_mfs(8). The end
result is essentially the same, but is accomplished in a completely
different way. Based on md-device, the
mdmfs
utility either creates a
tmpfs(5) filesystem, or it
configures an md(4) disk
using mdconfig(8), puts
a UFS file system on it (unless -P
was specified)
using newfs(8), and mounts
it using mount(8). It can
handle geom_uzip(4)
compressed disk images, as long as the kernel supports this GEOM class. All
the command line options are passed to the appropriate program at the
appropriate stage in order to achieve the desired effect.
When md-device is `auto',
mdmfs
uses
tmpfs(5) if it is present
in the kernel or can be loaded as a module, otherwise it falls back to using
md(4) auto-unit as if `md'
had been specified.
When md-device is `tmpfs',
mdmfs
mounts a
tmpfs(5) filesystem,
translating the -s
size option, if present, into a
`-o size=' mount option. Any -o
options on the
command line are passed through to the
tmpfs(5) mount. Options
specific to mdconfig(8)
or newfs(8) are
ignored.
When md-device does not result in
tmpfs(5) being used, then
an md(4) device is configured
instead. By default, mdmfs
creates a swap-based
(MD_SWAP
) disk with soft-updates enabled and mounts
it on mount-point. It uses the
md(4) device specified by
md-device. If md-device is
‘md
’ (no unit number), it will use
md(4)'s auto-unit feature to
automatically select an unused device. Unless otherwise specified with one
of the options below, it uses the default arguments to all the helper
programs.
The following options are available. Where possible, the option letter matches the one used by mount_mfs(8) for the same thing.
-a
maxcontig-d
option).-b
block-size-c
blocks-per-cylinder-group-D
-d
max-extent-size-E
path-mdconfig-e
maxbpg-F
fileMD_VNODE
) memory disk
backed by file.-f
frag-size-i
bytes-k
skel-l
-L
-M
MD_MALLOC
) instead of a swap-backed
disk.-m
percent-free-N
-X
.-n
-O
optimizationspace
and time
, which will
optimize for minimum space fragmentation and minimum time spent allocating
blocks, respectively.-o
mount-options-P
-F
is specified to create a
vnode-backed disk.-p
permissions-S
-s
size-F
is
not
specified. That is, this will work when the backing storage is some form
of memory, as opposed to a fixed-size file. The size may include the usual
SI suffixes (k, m, g, t, p). A number without a suffix is interpreted as a
count of 512-byte sectors.-t
-T
fstype-F
and -P
are used.-U
-S
flag, should such a need occur.-v
version1
or 2
. The default
is derived from the default of the
newfs(8) command.-w
user:group-X
The -F
and -s
options are passed to
mdconfig(8) as
-f
and -s
, respectively. The
-a
, -b
,
-c
, -d
,
-e
, -f
,
-i
, -m
and
-n
options are passed to
newfs(8) with the same
letter. The -O
option is passed to
newfs(8) as
-o
. The -o
option is passed
to mount(8) with the same
letter. The -T
option is passed to
mount(8) as
-t
. For information on semantics, refer to the
documentation of the programs that the options are passed to.
Create and mount a 32 megabyte swap-backed file system on /tmp:
mdmfs -s 32m md /tmp
The same file system created as an entry in /etc/fstab:
md /tmp mfs rw,-s32m 2 0
Create and mount a 16 megabyte malloc-backed file system on
/tmp using the /dev/md1
device; furthermore, do not use soft-updates on it and mount it
async
:
mdmfs -M -S -o async -s 16m md1
/tmp
Create and mount a geom_uzip(4) based compressed disk image:
mdmfs -P -F foo.uzip -oro md.uzip
/tmp/
Mount the same image, specifying the /dev/md1 device:
mdmfs -P -F foo.uzip -oro md1.uzip
/tmp/
Configure a vnode-backed file system and mount its first partition, using automatic device numbering:
mdmfs -P -F foo.img mds1a
/tmp/
Mount a vnode-backed cd9660 file system using automatic device numbering:
mdmfs -T cd9660 -P -F foo.iso md
/tmp
The mdmfs
utility, while designed to be
compatible with
mount_mfs(8), can be
useful by itself. Since
mount_mfs(8) had some
silly defaults, a “compatibility” mode is provided for the
case where bug-to-bug compatibility is desired.
Compatibility is enabled by starting mdmfs
with the name mount_mfs
or
mfs
(as returned by
getprogname(3)). In
this mode, the following behavior, as done by
mount_mfs(8), is
duplicated:
01777
as if -p
1777 was given on the command line.The mdmfs
utility appeared in
FreeBSD 5.0.
Dima Dorfman
October 31, 2019 | midnightbsd-3.1 |