mkfs(1M) MISC. REFERENCE MANUAL PAGES mkfs(1M)
NAME
mkfs (ufs) - construct a ufs file system
SYNOPSIS
mkfs [ -F ufs ] [generic_options] special
mkfs [ -F ufs ] [generic_options] [-o specific_options] spe-
cial size
DESCRIPTION
generic_options are options supported by the generic mkfs
command. current_options are options supported by the s5-
specific module of the mkfs command.
mkfs constructs a file system by writing on the special file
special unless the `-o N' flag has been specified. The
numeric size specifies the number of sectors in the file
system. mkfs builds a file system with a root directory and
a lost+found directory [see fsck(1M)]. The number of inodes
is calculated as a function of the file system size. The
options are:
-F ufs
Specifies the ufs-FSType.
-o Specify the ufs specific suboptions. The following
suboptions are available:
N Do not write the file system to the special file.
This suboption gives all the information needed to
create a file system but does not create it.
nsect
The number of sectors per track on the disk. The
default is 18.
ntrack
The number of tracks per cylinder on the disk.
The default is 9.
bsize
The primary block size for files on the file sys-
tem. It must be a power of two, currently
selected from 4096 or 8192 (the default).
fragsize
The fragment size for files on the file system.
The fragsize represents the smallest amount of
disk space that will be allocated to a file. It
must be a power of two currently selected from the
range 512 to 8192. The default is 1024.
cgsize
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mkfs(1M) MISC. REFERENCE MANUAL PAGES mkfs(1M)
The number of disk cylinders per cylinder group.
This number must be in the range 1 to 32. The
default is 16.
free The minimum percentage of free disk space allowed.
Once the file system capacity reaches this thres-
hold, only a privileged user is allowed to allo-
cate disk blocks. The default value is 10%.
rps The rotational speed of the disk, in revolutions
per second. The default is 60.
nbpi The number of bytes for which one inode block is
allocated. This parameter is currently set at one
inode block for every 2048 bytes.
opt Space or time optimization preference; s specifies
optimization for space, t specifies optimization
for time. The default is t.
apc The number of alternates per cylinder (SCSI dev-
ices only). The default is 0.
gap The expected time (in milliseconds) to service a
transfer completion interrupt and initiate a new
transfer on the same disk. It is used to decide
how much rotational spacing to place between suc-
cessive blocks in a file. The default is 4.
NOTES
The value of the nbpi operand in the output of mkfs -m is
always 2048, even if the file system was created with some
other value.
SEE ALSO
fsck(1M), generic mkfs(1M), dir(4), ufs(4).
Last change: UFS 2