newfs(8)newfs(8)NAME
newfs, mfs - Constructs a new UFS file system
SYNOPSIS
/usr/sbin/newfs [-N] [newfs-options] special-device [disk-type]
/usr/sbin/mfs [-F mount-options] [newfs-options] [special-device]
mount-node
OPTIONS
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 per‐
centage 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 permis‐
sions 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 speci‐
fies the maximum number of contiguous blocks that are laid out before
forcing a rotational delay (refer to the -d option); that is, the num‐
ber of blocks that can be combined into a single read request (clus‐
ter). 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 cylin‐
der 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 num‐
ber 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 replace‐
ments) 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 sys‐
tem. This option is primarily intended for use when mfs is
started by the mount(8) command.
DESCRIPTION
The newfs command creates a new UFS file system on the specified spe‐
cial-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 cre‐
ate 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 exam‐
ple 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.
NOTES
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.
ERRORS
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 cor‐
rectly. See the NOTES section for details. Warning: nn sec‐
tor(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 allo‐
cated
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 allo‐
cated and snumber of sectors are actually wasted. Warning: spe‐
cial-device and overlapping partition(s) are marked in use. If
you continue with the operation you can possibly destroy exist‐
ing data. CONTINUE? [y/n]
The specified partition overlaps with another partition or par‐
titions 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. CON‐
TINUE? [y/n]
The specified partition overlaps with another partition or par‐
titions that has the fstype field set. Warning: special-device
is marked in use for fstype in 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 exist‐
ing 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 par‐
tition 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. Parti‐
tion(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: 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 open. Error: special-device is 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 partition special-
device. 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 parti‐
tion 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. Quit‐
ting... 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 cor‐
rupted. Quitting...
See disklabel(8) for information on installing a disk label on a
disk.
EXAMPLES
The following examples show how to create an mfs file system: This
example creates an mfs of 128 Mbytes mounted on /tmp:
# /usr/sbin/mfs -s 250000 /tmp This example creates an mfs of
512 Mbytes (one half a Gbyte) mounted on /tmp:
#/usr/sbin/mfs -s 1000000 /tmp
FILES
Specifies the command path. Specifies the command path. Provides disk
geometry and file system partition information.
SEE ALSO
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)