NAME

mkfs − construct a file system

SYNOPSIS

/etc/mkfs special size [ nsect [ ntrack [ blksize [ fragsize [ ncpg [ minfree [ rps [ nbpi ] ] ] ] ] ] ] ]

DESCRIPTION

N.B.: File systems are normally created with the newfs(8) command.

Mkfs constructs a file system by writing on the special file special. 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(8)). The number of i-nodes is calculated as a function of the file system size. No boot program is initialized by mkfs (see newfs(8)).

The optional arguments allow fine tune control over the parameters of the file system:

nsect Specifies the number of sectors per track on the disk. 

ntrack Specifies the number of tracks per cylinder on the disk. 

blksize Gives the primary block size for files on the file system.  It must be a power of two, selected from 4096 or 8192. 

fragsize Gives the fragment size for files on the file system.  Represents the smallest amount of disk space that will be allocated to a file.  It must be a power of two, selected from the range 512 to 8192. 

ncpg Specifies the number of disk cylinders per cylinder group.  This number must be in the range 1 to 32. 

minfree Specifies the minimum percentage of free disk space allowed.  Once the file system capacity reaches this threshold, only the super-user is allowed to allocate disk blocks.  The default value is 10%. 

rps Specifies the number of revolutions per second, if a disk does not revolve at 60 revolutions per second.  Users with special demands for their file systems are referred to the paper cited below for a discussion of the tradeoffs in using different configurations. 

nbpi Specifies the number of bytes per inode, if a file system will have more or less than the average number of files.  Used to increase or decrease the number of inodes that are created. 

SEE ALSO

fs(5), dir(5), fsck(8), newfs(8), tunefs(8)

McKusick, Joy, Leffler; "A Fast File System for Unix", Computer Systems Research Group, Dept of EECS, Berkeley, CA 94720; TR #7, September 1982. 

BUGS

There should be some way to specify bad blocks. 

4BSD