newfs, mfs - Constructs a new UFS file system
/usr/sbin/newfs [-N] [newfs-options] special-device [disktype]
/usr/sbin/mfs [-F mount-options] [newfs-options] [specialdevice]
mount-node
This section describes the file system dependencies for
the UFS file systems.
Displays the file system parameters without creating the
file system.
The following newfs-options define the general layout
policies. The block size of the file system in bytes.
Note that the block size is fixed at 8KB. The fragment
size of the file system in bytes. The percentage of space
reserved from normal users; the minimum free space threshold
(minfree). The default value is 10%. See tunefs(8)
for more details on how to set this option. Allows a user
to set the permissions on the mfs root directory when it
is first created. By default, the mode is set to 1777.
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 is less than 10%, the default is to optimize for
space; if the value of minfree is greater than or equal to
10%, the default is to optimize for time. See tunefs(8)
for more details on how to set this option. This specifies
the maximum number of contiguous blocks that are laid
out before forcing a rotational delay (refer to the -d
option); that is, the number of blocks that can be combined
into a single read request (cluster). The default
value is 8. See tunefs(8) for more details on how to set
this option. This specifies the expected time (in milliseconds)
to service a transfer completion interrupt and
initiate a new transfer on the same disk. The default is
zero milliseconds. See tunefs(8) for more details on how
to set this option. 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. This specifies
the density of inodes in the file system. The default is
to create an inode for each 4096 bytes of data space. If
fewer inodes are desired, a larger number should be used;
to create more inodes a smaller number should be given.
The number of cylinders per cylinder group in a file system.
The default value is 16. The size of the file system
in sectors.
The following options override the default sizes for the
disk geometry. The default values are taken from the disk
label. Changing the defaults is useful only if you are
using newfs to build (create) a file system whose raw
image will eventually be used on a different type of disk
(on a write-once disk, for example). Note that changing
any of these values from their defaults makes it impossible
for fsck to find the alternate superblocks if the
standard superblock is lost. The speed of the disk in
revolutions per minute. The size of a sector in bytes
(almost never anything but 512). The number of sectors
per track available for data allocation by the file system.
This does not include sectors reserved at the end of
each track for bad block replacement (see -p). The number
of tracks per cylinder available for data allocation by
the file system. Spare sectors (bad sector replacements)
are physical sectors that occupy space at the end of each
track. They are not counted as part of the sectors per
track (-u) since they are not available to the file system
for data allocation. Spare sectors (bad sector replacements)
are physical sectors that occupy space at the end
of the last track in the cylinder. They are deducted from
the sectors per track (-u) of the last track of each
cylinder since they are not available to the file system
for data allocation. Used to describe perturbations in
the media format to compensate for a slow controller.
Interleave is physical sector interleave on each track,
specified as the denominator of the ratio: sectors
read/sectors passed over.
Thus, an interleave of 1/1 implies contiguous layout,
while 1/2 implies logical sector 0 (zero) is
separated by one sector from logical sector 1.
Used to describe perturbations in the media format
to compensate for a slow controller. Track skew is
the offset of sector 0 (zero) on track N relative
to sector 0 (zero) on track N-1 on the same cylinder.
This option applies only to mfs. It is used
for providing a decimal numeric value to be passed
as mount options when running as a memory based
file system. This option is primarily intended for
use when mfs is started by the mount(8) command.
The newfs command creates a new UFS file system on the
specified special-device of type disk-type.
Note
The newfs command cannot be used to create Advanced File
System (AdvFS) domains. Instead, use the mkfdmn command,
as described in the mkfdmn(8) reference page.
Use the disklabel command to label disks and the newfs
command to create UFS file systems on the disks.
If you have labeled the disk by using the disklabel command,
newfs builds a UFS file system on the specified
device, basing its defaults on the information in the disk
label. If the disk has not been labeled using the disklabel
command, newfs fails, displaying the message
disk not labeled. When this happens, use the disklabel
command to install a label.
The mfs command builds a memory file system (mfs), which
is a UFS file system in virtual memory, and mounts it on
the specified mount-node. When the file system is
unmounted, mfs exits and the contents of the file system
are lost. If mfs is sent a signal while running, for
example during system shutdown, it attempts to unmount its
corresponding file system. The parameters for mfs are
almost the same as those for newfs. For a memory file
system, the special-device file provides only a set of
configuration parameters, including the size of the virtual
memory segment to allocate. If the special-device
file is omitted, you must specify the segment size. The
special-device file is usually the primary swap area,
because that is where the file system is backed up when
free memory gets low and the memory supporting the file
system has to be paged.
You can enable /tmp as a memory file system by adding an
entry in the /etc/fstab file. For example, the following
line creates a 10 Megabyte memory file system, mounted on
/tmp:
-s20480 /tmp mfs rw 1 0
Note that the contents of a memory file system are lost
whenever a reboot or unmount is performed.
You must be superuser to use both commands.
When using newfs to create a UFS file system on an LSM
volume, follow these guidelines: The disk-type variable
may be specified to enable newfs to obtain disk attributes
such as number of sectors (ns), number of tracks (nt), and
number of cylinders (nc) from the /etc/disktab file. The
newfs command may get this information from /etc/disktab
because an LSM volume has no disk label. When specifying
disk-type, you can use any entry in /etc/disktab that has
positive values for the disk attributes (except rx##
entries). Since the entries for disks with dynamic geometry
(such as RAID, re, SWXCR, and hsz##) have a value of
-1 for these attributes, such disk types cannot be specified
to newfs. Instead, use another entry whose characteristics
match those of the volume (for example, rz##).
Or, you can create a customized entry in /etc/disktab.
The -s option can be omitted, because newfs queries LSM
for the size of the LSM volume.
You may receive the following messages when using the
newfs command: newfs: /dev/rvol/diskgroup/volname: only 0
partitions
This error occurs when you attempt to create a file
system on an LSM volume and fail to specify the
disk-type parameter correctly. See the NOTES section
for details. Warning: nn sector(s) in last
cylinder unallocated
This message is for UFS only. It requires no user
action. The message indicates that if nn sectors
are added to the size of the file system, it will
be an integral number of cylinders. Disk space is
not wasted. Usually, cylinder boundaries are
ignored when partitions are allocated. Warning:
inode blocks/cyl group (inumber) >= data blocks
(dnumber) in last cylinder group. This implies
snumber sector(s) cannot be allocated
This message requires no user action. It indicates
that inumber of file system blocks were needed to
allocate the inode table but only dnumber of file
system blocks were available in the last cylinder
group. The last cylinder group could not be allocated
and snumber of sectors are actually wasted.
Warning: special-deviceand overlapping partition(s)
are marked in use. If you continue with the operation
you can possibly destroy existing data. CONTINUE?
[y/n]
The specified partition overlaps with another partition
or partitions that has the fstype field set.
Warning: partition(s) which overlap special-device
are marked in use. If you continue with the operation
you can possibly destroy existing data. CONTINUE?
[y/n]
The specified partition overlaps with another partition
or partitions that has the fstype field set.
Warning: special-deviceis marked in use for
fstypein the disklabel. The partition you are
changing already has a file system on it. This is
not an error just a warning.
The partition you are changing already has a file
system on it. special-device is marked in use for
fstype in the disklabel. If you continue with the
operation you can possibly destroy existing data.
CONTINUE? [y/n]
This message indicates that you tried to create a
file system on a partition that is not currently in
active use but is marked for use in the disk
label's partition map. For example, the partition
may be part of an LSM volume or an AdvFS domain.
If you know that the partition you specified to
newfs does not contain any useful data, you can
choose to override the warning. In this case, the
fstype in the disk label will be modified to
4.2BSD.
Note that you can use the command disklabel -s to
set the fstype in the disk label to unused for partitions
that do not contain any valid data. See
disklabel(8) for more information. Partition(s)
which overlap special-device are marked in use. If
you continue with the operation you can possibly
destroy existing data. CONTINUE? [y/n]
This message indicates that the partition you specified
is not marked for use, but other, overlapping
partitions on the disk are marked for use. If you
override this warning, the fstype in the disk's
label will be modified. The partition you specified
to newfs will be marked as in use by the UFS file
system and labeled with 4.2BSD. All overlapping
partitions will be marked UNUSED. special-device
or an overlapping partition is open. Quitting...
This message indicates that you tried to create a
file system on a partition that is actively in use.
Error: the disklabel for special-device does not
exist or is corrupted. Quitting ....
The specified device either does not have a disklabel
or the disklabel is corrupted. Error: specialdeviceor
an overlapping partition is open. Quitting
....
This message indicates that you tried to create a
file system on a partition that is open. Error:
special-deviceis an invalid device or cannot be
opened. Quitting ....
The specified device is either an invalid device or
it cannot be opened. Error: the disklabel for special-device
could not be updated. Quitting ....
This message indicates that the disklabel on the
specified device could not be updated. Error::
unable to check special-device against active AdvFS
domains because the directory /etc/fdmns seems to
be missing or wrong. Quitting ....
This message indicates that there was a failure
when checking overlap with AdvFS domains. Either
/etc/fdmns or /etc/fdmns/dom are not active domains
or they do not exist. Error: unable to check special-device
against active swap devices because
special swap files are missing. Quitting ....
This message indicates that there was a failure
when checking overlap with active swap devices.
The special device files associated with active
swap devices are invalid. Error: unknown overlap
condition errno encountered for partitionspecialdevice.
Quitting ....
This message indicates that an unknown error was
detected.
The following examples illustrate some of these messages:
Creating a file system on a partition that is marked for
use:
# /usr/sbin/newfs /dev/rdisk/dsk11g
/dev/rdisk/dsk11g is marked in use for LSMpubl in
the disklabel. If you continue with the operation
you can possibly destroy existing data. CONTINUE?
[y/n]
Partition g of disk dsk11 is part of a disk marked
for use by LSM. If LSM is not actively using this
partition and the partition does not contain any
useful data, you may want to override this warning,
by answering y. In this case, partition g will be
marked as 4.2BSD in the disk label. Creating a
file system on a partition whose overlapping partitions
are marked for use:
# /usr/sbin/newfs /dev/rdisk/dsk11c
Partition(s) which overlap /dev/rdisk/dsk11c are
marked in use. If you continue with the operation
you can possibly destroy existing data. CONTINUE?
[y/n]
If you answer y, partition c on disk dsk11 will be
marked 4.2BSD in the disk label and all partitions
that overlap c will be marked UNUSED. Creating a
file system on a partition that is open:
# /usr/sbin/newfs /dev/rdisk/dsk11g
/dev/rdisk/dsk11g or an overlapping partition is
open. Quitting... Creating a file system on disk
that does not have a disk label:
# /usr/sbin/newfs /dev/rdisk/dsk11c
The disklabel for /dev/rdisk/dsk11c does not exist
or is corrupted. Quitting...
See disklabel(8) for information on installing a
disk label on a disk.
The following examples show how to create an mfs file system.
Both examples assume that the process system
attributes are at the system default values, per-procdata-size
is set at 134217728 bytes and max-per-proc-datasize
is set at 1073741824 bytes (1 Gbyte).
The following example creates an mfs of 128 Mbytes,
mounted on /tmp:
# /usr/sbin/mfs -s250000 /tmp
The following example creates an mfs of 512 Mbytes, which
is one half Gbyte), mounted on /tmp. Note that two events
must happen before you create and mount the mfs file system.
First, the process system attribute per-proc-datasize
must be increased to a new maximum value that is
equal to or greater than the size of the mfs file system
you want to create. Second, the system must be shut down
and rebooted so that the new per-proc-data-size value can
be placed in both the in-memory and the on-disk system
configuration data bases. Modify the /etc/sysconfigtab
file to change the entry for the per-proc-data-size to the
following:
per_proc_data_size = 536870912
See sysconfigdb(8) for information on how to make
this change. Shut down and reboot the system to
synchronize the in-memory and on-disk system configuration
data bases. Create the 512 Mbyte mfs,
mounted on /tmp:
#/usr/sbin/mfs -s 1000000 /tmp
Specifies the command path. Specifies the command path.
Provides disk geometry and file system partition information.
Commands: chmod(1), disklabel(8), fsck(8), mkfdmn(8),
mount(8), tunefs(8)
Files: disktab(4), fstab(4)
Functions: check_usage(3), set_usage(3)
newfs(8)
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