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 system. 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

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 devices 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 successive 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).