mke2fs - create a Linux second extended file system
SYNOPSIS
mke2fs [ -c | -l filename ] [ -b block-size ] [ -f frag
ment-size ] [ -i bytes-per-inode ] [ -j ] [ -J journal-
options ] [ -N number-of-inodes ] [ -n ] [ -m reserved-
blocks-percentage ] [ -o creator-os ] [ -O feature[,...]
] [ -q ] [ -r fs-revision-level ] [ -R raid-options ] [ -v
] [ -F ] [ -L volume-label ] [ -M last-mounted-directory ]
[ -S ] [ -T filesystem-type ] [ -V ] device [ blocks-count
]
mke2fs -O journal_dev [ -b block-size ] [ -L volume-label
] [ -n ] [ -q ] [ -v ] external-journal
DESCRIPTION
mke2fs is used to create a Linux second extended file sys
tem on a device (usually a disk partition). device is the
special file corresponding to the device (e.g /dev/hdXX).
blocks-count is the number of blocks on the device. If
omitted, mke2fs automagically figures the file system
size.
OPTIONS
-b block-size
Specify the size of blocks in bytes. Valid block
size vales are 1024, 2048 and 4096 bytes per block.
If omitted, mke2fs block-size is determined by the
file system size and the expected usage of the
filesystem (see the -T option).
-c Check the device for bad blocks before creating the
file system, using a fast read-only test.
-f fragment-size
Specify the size of fragments in bytes.
-F Force mke2fs to run, even if the specified device
is not a block special device, or appears to be
mounted.
-i bytes-per-inode
Specify the bytes/inode ratio. mke2fs creates an
inode for every bytes-per-inode bytes of space on
the disk. The larger the bytes-per-inode ratio,
the fewer inodes will be created. This value gen
erally 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 cre
ated, so be careful deciding the correct value for
this parameter.
-J option is not specified, the default journal
parameters will be used to create an appropriately
sized journal (given the size of the filesystem)
stored within the filesystem. Note that you must
be using a kernel which has ext3 support in order
to actually make use of the journal.
-J journal-options
Create the ext3 journal using options specified on
the command-line. Journal options are comma sepa
rated, and may take an argument using the equals
('=') sign. The following journal options are
supported:
size=journal-size
Create a journal stored in the filesys
tem of size journal-size megabytes.
The size of the journal must be at
least 1024 filesystem blocks (i.e., 1MB
if using 1k blocks, 4MB if using 4k
blocks, etc.) and may be no more than
102,400 filesystem blocks. The journal
must fit within the newly created
filesystem.
device=external-journal
Attach the filesystem to the journal
block device located on external-jour
nal. The external journal must already
have been created using the command
mke2fs -O journal_dev external-journal
Note that external-journal must have
been created with the same block size
as the new filesystem.
Only one of the size or device options can be given
for a filesystem.
-l filename
Read the bad blocks list from filename.
-L Set the volume label for the filesystem.
-m reserved-blocks-percentage
Specify the percentage of the filesystem blocks
reserved for the super-user. This value defaults
to 5%.
-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
-n causes mke2fs to not actually create a filesystem,
but display what it would do if it were to create a
filesystem.
-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
bytes-per-inode ratio). This allows the user to
specify the number of desired inodes directly.
-o creator-os
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
mke2fs executable.
-O feature[,...]
Create filesystem with given features (filesystem
options). Currently, the sparse_super and filetype
features are turned on by default unless mke2fs is
run on a system with a pre-2.2 Linux kernel.
Filesystems that may need to mounted on pre-2.2
kernels should be created with -O none (or -r 0 for
1.2 kernels) which will disable these features,
even if mke2fs is run on a system which can support
them.
The following filesystem options are supported:
sparse_super
Create a filesystem with fewer
superblock backup copies (saves space
on large filesystems).
filetype
Store file type information in direc
tory entries.
has_journal
Create an ext3 journal (as if using the
-j option).
journal_dev
Create an external ext3 journal on the
given device instead of a regular ext2
filesystem. Note that external-journal
must be created with the same block
size as the filesystems that will be
using it.
-q Quiet execution. Useful if mke2fs is run in a
-r revision
Set the filesystem revision for the new filesystem.
Note that 1.2 kernels only support revision 0
filesystems. The default is to create revision 1
filesystems.
-R raid-options
Set raid-related options for the filesystem. Raid
options are comma separated, and may take an argu
ment using the equals ('=') sign. The following
options are supported:
stride=stripe-size
Configure the filesystem for a RAID
array with stripe-size filesystem
blocks per stripe.
-S Write superblock and group descriptors only. This
is useful if all of the superblock and backup
superblocks are corrupted, and a last-ditch recov
ery method is desired. It causes mke2fs to reini
tialize the superblock and group descriptors, while
not touching the inode table and the block and
inode bitmaps. The e2fsck program should be run
immediately after this option is used, and there is
no guarantee that any data will be salvageable. It
is critical to specify the correct filesystem
blocksize when using this option, or there is no
chance of recovery.
-T fs-type
Specify how the filesystem is going to be used, so
that mke2fs can chose optimal filesystem parameters
for that use. The supported filesystem types are:
news one inode per 4kb block
largefile one inode per megabyte
largefile4 one inode per 4 megabytes
-v Verbose execution.
-V Print the version number of mke2fs and exit.
AUTHOR
This version of mke2fs has been written by Theodore Ts'o
<tytso@mit.edu>.
BUGS
mke2fs accepts the -f option but currently ignores it
because the second extended file system does not support
There may be other ones. Please, report them to the
author.
AVAILABILITY
mke2fs is part of the e2fsprogs package and is available
from http://e2fsprogs.sourceforge.net.
SEE ALSO
badblocks(8), dumpe2fs(8), e2fsck(8), tune2fs(8)
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