NAME
newfs_lfs
- construct a new LFS file system
SYNOPSIS
newfs_lfs
[newfs_lfs-options]
special
DESCRIPTION
newfs_lfs
builds a log-structured file system on the specified special
device basing its defaults on the information in the disk label.
Before running
newfs_lfs
the disk must be labeled using
disklabel(8),
the proper fstype is 4.4LFS.
Reasonable values for the
fsize
,
bsize
,
and
sgs
fields are 1024, 8192, and 7 respectively.
The following options define the general layout policies.
- -A
-
Attempt to compute the appropriate segment size using the formula
4 * bandwidth * access time.
The disk is tested for twenty seconds
to discover its bandwidth and seek time.
- -B logical-segment-size
-
The logical segment size of the file system in bytes.
If not specified, the segment size is computed by left-shifting
the partition label's block size by the amount indicated in the
partition table's segshift.
If the disklabel indicates a zero block size or segment shift,
a compile-time default segment size of 1M is used.
- -b block-size
-
The block size of the file system in bytes.
If not specified, the block size is taken from the partition label,
or if the partition label indicates 0,
a compile-time default of 8K is used.
- -F
-
Force creation of an LFS even on a partition labeled as another type.
newfs_lfs
will use compile-time default values for block and fragment size, and segment
shift, unless these are overridden by command-line flags.
- -f fragment-size
-
The fragment size of the file system in bytes.
If not specified, the fragment size is taken from the partition label,
or if the partition label indicates 0,
a compile-time default of 1K is used.
- -I interleave
-
Specify the interleave between segments.
The default is zero.
- -i
-
The size of an inode block, in bytes.
The default is to use the same size as a fragment,
or in a v1 filesystem, the same size as a data block.
- -L
-
Create a log-structured file system (LFS).
This is the default, and this
option is provided for compatibility only.
- -M nsegs
-
Specify
lfs_minfreeseg,
the number of segments left out of the amount allocated to user data.
A higher number increases cleaner performance, while a lower number
gives more usable space.
The default is based on the size of the filesystem, either 5% of the
total number of segments or 20 segments, whichever is larger.
- -m free space %
-
The percentage of space reserved from normal users; the minimum
free space threshold.
The default value used is 10%.
- -N
-
Do not actually create the filesystem.
- -O offset
-
Start the first segment this many sectors from the beginning of the
partition.
The default is zero.
- -R nsegs
-
Specify
lfs_resvseg,
the number of segments set aside for the exclusive use of the cleaner.
A larger figure reduces the likelihood of running out of clean segments,
but if
is too close to
lfs_minfreeseg,
the cleaner will run without ceasing when the filesystem becomes close to
full. The default is the larger of 15 or the quantity
lfs_minfreeseg
/ 2 + 1 .
- -r ident
-
For a v2 filesystem, specify the roll-forward identifier for the
filesystem.
This identifier, a 32-bit numeric quantity,
should be different from that of any LFS that may previously
have existed on the same disk.
By default the identifier is chosen at random.
- -s size
-
The size of the file system in sectors.
- -v version
-
Make a filesystem with the specified disk layout version.
Valid options are 1 or 2 (the default).
Note,
however, that LFS version 1 is deprecated.
SEE ALSO
disktab(5),
disklabel(8),
diskpart(8),
dumplfs(8)
HISTORY
A
newlfs
command appeared in
4.4BSD,
and was renamed to
newfs_lfs
for
NetBSD1.4.