e2fsprogs/misc/mke2fs.8.in

.\" -*- nroff -*-
.\" Copyright 1993, 1994, 1995 by Theodore Ts'o.  All Rights Reserved.
.\" This file may be copied under the terms of the GNU Public License.
.\" 
.TH MKE2FS 8 "@E2FSPROGS_MONTH@ @E2FSPROGS_YEAR@" "E2fsprogs version @E2FSPROGS_VERSION@"
.SH NAME
mke2fs \- create a Linux second extended file system
.SH SYNOPSIS
.B mke2fs
[
.B \-c
| 
.\" .B \-t
.\" .I test
.\" |
.B \-l
.I filename
]
[
.B \-b
.I block-size
]
[
.B \-f
.I fragment-size
]
[
.B \-i
.I bytes-per-inode
]
[
.B \-j
.I journal-options
]
[
.B \-N
.I number-of-inodes
]
[
.B -n
]
[
.B \-m
.I reserved-blocks-percentage
]
[
.B \-o
.I creator-os
]
[
.B \-O 
.IR feature [,...]
]
[
.B \-q
]
[
.B \-r
.I fs-revision-level
]
[
.B \-R
.I raid_options
]
[
.B \-s
.I sparse-super-flag
]
[
.B \-v
]
[
.B \-F
]
[
.B \-L
.I volume-label
]
[
.B \-M
.I last-mounted-directory
]
[
.B \-S
]
[
.B \-T
.I filesystem-type
]
[
.B \-V
]
.I device
[
.I blocks-count
]
.SH DESCRIPTION
.B mke2fs
is used to create a Linux second extended file system on a device (usually
a disk partition).
.I device
is the special file corresponding to the device (e.g 
.IR /dev/hdXX ).
.I blocks-count
is the number of blocks on the device.  If omitted,
.B mke2fs
automagically figures the file system size.
.SH OPTIONS
.TP
.BI \-b " block-size"
Specify the size of blocks in bytes.  Valid block size vales are 1024, 
2048 and 4096 bytes per block.  If omitted,
.B mke2fs
block-size is determined by the file system size and the expected usage
of the filesystem (see the
.B \-T
option).
.TP
.B \-c
Check the device for bad blocks before creating the file system, using a
fast read-only test.
.TP
.BI \-f " fragment-size"
Specify the size of fragments in bytes.
.TP
.BI \-i " bytes-per-inode"
Specify the bytes/inode ratio. 
.B mke2fs
creates an inode for every
.I bytes-per-inode
bytes of space on the disk.  
The larger the 
.I bytes-per-inode
ratio, the fewer inodes will be created.
This value generally shouldn't be smaller than
the blocksize of the filesystem, since then too many inodes will be made.  
Be warned that is not possible to expand the number of inodes on a 
filesystem after it is created, so be careful decided the correct
value for this parameter. 
.TP
.BI \-j " journal options"
Build the ext2 filesystem with the ext3 journaling feature enabled.  
Journal options are comma
separated, and may take an argument using the equals ('=')  sign.
Currently two options are supported,
.I size
and
.IR device .
One these two options must be specified when 
building the journal.
The 
.I size 
option takes a numerical argument which specifies the size of the 
journal in MB (1024*1024 bytes).  Any size between 4MB and 100MB may be used.
Use of this option implies that the journal will be stored in the 
filesystem, so it must be small enough to fit into the filesystem.
The 
.I device
option takes a filename which specifies a block device (external 
to the filesystem) which will contain the external journal.  
.TP
.B \-n
causes mke2fs to not actually create a filesystem, but display what it 
would do if it were to create a filesystem.
.TP
.BI \-N " number-of-inodes"
overrides the default calculation of the number of inodes that should be 
reserved for the filesystem (which is based on the number of blocks and 
the 
.I bytes-per-inode
ratio).  This allows the user to specify the number 
of desired inodes directly.
.TP
.BI \-O " feature\fR[,...]"
Create the filesystem with the listed set of features 
(filesystem options).  The following features are supported: 
.IR sparse_super ,
which cause the filesystem to use sparse superblocks, and
.IR filetype ,
which will cause the filesystem to store file type information in 
directory entries.   Currently, both features are turned on by default
unless 
.B mke2fs
is run on a system with a pre-2.2 Linux kernel.
.B Warning:
Pre-2.2 Linux kernels do not properly 
support the filesystems that use either of these two features.   Filesystems 
that may need to mounted on pre-2.2 kernels should be created with 
.B -O
.I none
which will disable both of these features, even if 
.B mke2fs 
is run on a system which can support these features.
.TP
.BI \-l " filename"
Read the bad blocks list from
.I filename.
\.
.TP
.BI -m " reserved-blocks-percentage"
Specify the percentage of reserved blocks for the super-user.  This value
defaults to 5%.
.\" .TP
.\" .BI \-t " test"
.\" Check the device for bad blocks before creating the file system
.\" using the specified test.
.TP
.B \-o
Manually override the default value of the "creator os" field of the 
filesystem.  Normally the creator field is set by default to the native OS
of the
.B mke2fs
executable.
.TP
.B \-q
Quiet execution.  Useful if 
.B mke2fs
is run in a script.
.TP
.BI \-s " sparse-super-flag"
If 
.I sparse-super-flag
is 1, then turn on the sparse superblock flag in the superblock.  
.B Note:
This option is deprecated; use the 
.B \-O
option instead.
.TP
.B \-v
Verbose execution.
.TP
.B \-F
Force 
.B mke2fs
to run, even if the specified device is not a 
block special device, or appears to be mounted.
.TP
.B \-L
Set the volume label for the filesystem.
.TP
.B \-M
Set the last mounted directory for the filesystem.  This might be useful 
for the sake of utilities that key off of the last mounted directory to 
determine where the filesytem should be mounted.
.TP
.BI -r " revision"
Set the filesystem revision for the new filesystem.  Note that 1.2
kernels only support revision 0 filesystems.
.TP
.BI \-R " raid_options"
Set raid-related options for the filesystem.  Raid options are comma
separated, and may take an argument using the equals ('=')  sign.
Currently the only supported argument is 
.I stride
which takes as its argument the number of blocks in a RAID stripe.
.TP
.B \-S
Write superblock and group descriptors only.  This is useful if all of
the superblock and backup superblocks are corrupted, and a last-ditch
recovery method is desired.  It causes 
.B mke2fs
to reinitialize the 
superblock and group descriptors, while not touching the inode table
and the block and inode bitmaps.  The
.B e2fsck
program should be run immediately after this option is used, and there
is no guarantee that any data will be salvageable.
.TP
.BI \-T " fs-type"
Specify how the filesystem is going to be used, so that mke2fs can 
chose optimal filesystem parameters for that use.  The only
currently supported filesystem types are:
.BR news ,
which reserves space for  one inode per 4kb block,
.BR largefile
which allocates one inode per megabyte, and
.BR largefile4
which allocates one inode per 4 megabytes.  
.TP
.B \-V
Print the version number of 
.B mke2fs
and exit.
.SH AUTHOR
This version of
.B mke2fs
has been written by Theodore Ts'o <tytso@mit.edu>.
.SH BUGS
.B mke2fs
accepts the
.B \-f
option but currently ignores it because the second
extended file system does not support fragments yet.
.br
There may be some other ones.  Please, report them to the author.
.SH AVAILABILITY
.B mke2fs
is part of the e2fsprogs package and is available for anonymous 
ftp from tsx-11.mit.edu in /pub/linux/packages/ext2fs.
.SH SEE ALSO
.BR badblocks (8),
.BR dumpe2fs (8),
.BR e2fsck (8),
.BR tune2fs (8)