MKFS(8) Maintenance Procedures MKFS(8)


mkfs - construct a file system


mkfs [-F FSType] [generic_options]
[-o FSType-specific_options] raw_device_file


The mkfs utility constructs a file system on the raw_device_file by
calling the specific mkfs module indicated by -F FSType.

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

generic_options are independent of file system type. FSType-
specific_options is a comma-separated list of keyword=value pairs (with
no intervening spaces), which are FSType-specific. raw_device_file
specifies the disk partition on which to write the file system. It is
required and must be the first argument following the specific_options
(if any). operands are FSType-specific. See the FSType-specific manual
page of mkfs (for example, mkfs_ufs(8)) for a detailed description.


The following are the generic options for mkfs:

Specify the FSType to be constructed. If -F is not specified, the
FSType is determined from /etc/vfstab by matching the
raw_device_file with a vfstab entry, or by consulting the
/etc/default/fs file.

Echo the complete command line, but do not execute the command. The
command line is generated by using the options and arguments
provided and adding to them information derived from /etc/vfstab
or /etc/default/fs. This option may be used to verify and
validate the command line.

Return the command line which was used to create the file system.
The file system must already exist. This option provides a means of
determining the command used in constructing the file system.

Specify FSType-specific options. See the manual page for the mkfs
module specific to the file system type.


See largefile(7) for the description of the behavior of mkfs when
encountering files greater than or equal to 2 Gbyte ( 2^31 bytes).


Default file system type. Default values can be set
for the following flags in /etc/default/fs. For
example: LOCAL=ufs

The default partition for a command if no
FSType is specified.

List of default parameters for each file system


vfstab(5), attributes(7), largefile(7), mkfs_ufs(8), newfs(8)

Manual pages for the FSType-specific modules of mkfs.


This command might not be supported for all FSTypes.

You can use lofiadm to create a file that appears to a mkfs command as a
raw device. You can then use a mkfs command to create a file system on
that device. See lofiadm(8) for examples of creating a UFS and a PC (FAT)
file system (using mkfs_ufs(8) and mkfs_pcfs(8)) on a device created by

November 17, 2000 MKFS(8)