NAME

mkfs − construct a file system

SYNOPSIS

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

DESCRIPTION

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

mkfs constructs a file system by writing on the special file special unless the −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(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)).

OPTIONS

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

nsect The number of sectors per track on the disk

ntrack 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, currently selected from 4096 or 8192. 

fragsize
gives 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. 

ncpg 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 If a disk does not revolve at 60 revolutions per second, this parameter may be specified. 

nbpi Number of bytes for which one i-node block is allocated.  This parameter is currently set at one i-node block for every 2048 bytes. 

opt Space or time optimization preference; “s” specifies optimizatiion for space, “t” specifies optimization for time. 

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. 

SEE ALSO

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

McKusick, Joy, Leffler; A Fast File System for Unix, System Internals Manual for the Sun Workstation.

Sun Release 3.5  —  Last change: 11 April 1986