860 lines
25 KiB
Groff
860 lines
25 KiB
Groff
.\" -*- nroff -*-
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.\" Copyright 1993, 1994, 1995 by Theodore Ts'o. All Rights Reserved.
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.\" This file may be copied under the terms of the GNU Public License.
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.\"
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.TH MKE2FS 8 "@E2FSPROGS_MONTH@ @E2FSPROGS_YEAR@" "E2fsprogs version @E2FSPROGS_VERSION@"
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.SH NAME
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mke2fs \- create an ext2/ext3/ext4 filesystem
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.SH SYNOPSIS
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.B mke2fs
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[
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.B \-c
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.B \-l
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.I filename
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]
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[
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.B \-b
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.I block-size
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]
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[
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.B \-C
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.I cluster-size
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]
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[
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.B \-d
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.I root-directory
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]
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[
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.B \-D
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]
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[
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.B \-g
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.I blocks-per-group
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]
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[
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.B \-G
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.I number-of-groups
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]
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[
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.B \-i
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.I bytes-per-inode
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]
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[
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.B \-I
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.I inode-size
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]
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[
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.B \-j
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]
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[
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.B \-J
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.I journal-options
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]
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[
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.B \-N
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.I number-of-inodes
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]
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[
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.B \-n
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]
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[
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.B \-m
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.I reserved-blocks-percentage
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]
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[
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.B \-o
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.I creator-os
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]
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[
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.B \-O
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[^]\fIfeature\fR[,...]
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]
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[
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.B \-q
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]
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[
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.B \-r
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.I fs-revision-level
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]
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[
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.B \-E
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.I extended-options
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]
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[
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.B \-v
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]
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[
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.B \-F
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]
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[
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.B \-L
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.I volume-label
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]
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[
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.B \-M
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.I last-mounted-directory
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]
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[
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.B \-S
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]
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[
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.B \-t
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.I fs-type
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]
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[
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.B \-T
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.I usage-type
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]
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[
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.B \-U
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.I UUID
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]
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[
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.B \-V
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]
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[
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.B \-e
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.I errors-behavior
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]
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[
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.B \-z
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.I undo_file
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]
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.I device
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[
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.I fs-size
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]
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@JDEV@.sp
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@JDEV@.B "mke2fs \-O journal_dev"
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@JDEV@[
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@JDEV@.B \-b
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@JDEV@.I block-size
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@JDEV@]
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.\" No external-journal specific journal options yet (size is ignored)
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.\" @JDEV@[
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.\" @JDEV@.B \-J
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.\" @JDEV@.I journal-options
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.\" @JDEV@]
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@JDEV@[
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@JDEV@.B \-L
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@JDEV@.I volume-label
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@JDEV@]
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@JDEV@[
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@JDEV@.B \-n
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@JDEV@]
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@JDEV@[
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@JDEV@.B \-q
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@JDEV@]
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@JDEV@[
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@JDEV@.B \-v
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@JDEV@]
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@JDEV@.I external-journal
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@JDEV@[
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@JDEV@.I fs-size
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@JDEV@]
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.SH DESCRIPTION
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.B mke2fs
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is used to create an ext2, ext3, or ext4 filesystem, usually in a disk
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partition (or file) named by
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.IR device .
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.PP
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The file system size is specified by
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.IR fs-size .
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If
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.I fs-size
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does not have a suffix, it is interpreted as power-of-two kilobytes,
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unless the
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.B \-b
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.I blocksize
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option is specified, in which case
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.I fs-size
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is interpreted as the number of
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.I blocksize
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blocks. If the fs-size is suffixed by 'k', 'm', 'g', 't'
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(either upper-case or lower-case), then it is interpreted in
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power-of-two kilobytes, megabytes, gigabytes, terabytes, etc.
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If
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.I fs-size
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is omitted,
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.B mke2fs
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will create the file system based on the device size.
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.PP
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If
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.B mke2fs
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is run as
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.B mkfs.XXX
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(i.e.,
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.BR mkfs.ext2 ,
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.BR mkfs.ext3 ,
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or
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.BR mkfs.ext4 )
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the option
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.B \-t
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.I XXX
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is implied; so
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.B mkfs.ext3
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will create a file system for use with ext3,
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.B mkfs.ext4
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will create a file system for use with ext4, and so on.
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.PP
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The defaults of the parameters for the newly created filesystem, if not
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overridden by the options listed below, are controlled by the
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.B /etc/mke2fs.conf
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configuration file. See the
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.BR mke2fs.conf (5)
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manual page for more details.
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.SH OPTIONS
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.TP
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.BI \-b " block-size"
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Specify the size of blocks in bytes. Valid block-size values are 1024,
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2048 and 4096 bytes per block. If omitted,
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block-size is heuristically determined by the filesystem size and
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the expected usage of the filesystem (see the
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.B \-T
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option). If
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.I block-size
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is preceded by a negative sign ('-'), then
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.B mke2fs
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will use heuristics to determine the
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appropriate block size, with the constraint that the block size will be
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at least
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.I block-size
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bytes. This is useful for certain hardware devices which require that
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the blocksize be a multiple of 2k.
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.TP
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.B \-c
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Check the device for bad blocks before creating the file system. If
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this option is specified twice, then a slower read-write
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test is used instead of a fast read-only test.
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.TP
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.B \-C " cluster-size"
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Specify the size of cluster in bytes for filesystems using the bigalloc
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feature. Valid cluster-size values are from 2048 to 256M bytes per
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cluster. This can only be specified if the bigalloc feature is
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enabled. (See the
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.B ext4 (5)
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man page for more details about bigalloc.) The default cluster size if
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bigalloc is enabled is 16 times the block size.
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.TP
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.BI \-d " root-directory"
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Copy the contents of the given directory into the root directory of the
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filesystem.
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.TP
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.B \-D
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Use direct I/O when writing to the disk. This avoids mke2fs dirtying a
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lot of buffer cache memory, which may impact other applications running
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on a busy server. This option will cause mke2fs to run much more
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slowly, however, so there is a tradeoff to using direct I/O.
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.TP
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.BI \-e " error-behavior"
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Change the behavior of the kernel code when errors are detected.
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In all cases, a filesystem error will cause
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.BR e2fsck (8)
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to check the filesystem on the next boot.
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.I error-behavior
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can be one of the following:
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.RS 1.2i
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.TP 1.2i
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.B continue
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Continue normal execution.
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.TP
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.B remount-ro
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Remount filesystem read-only.
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.TP
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.B panic
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Cause a kernel panic.
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.RE
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.TP
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.BI \-E " extended-options"
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Set extended options for the filesystem. Extended options are comma
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separated, and may take an argument using the equals ('=') sign. The
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.B \-E
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option used to be
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.B \-R
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in earlier versions of
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.BR mke2fs .
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The
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.B \-R
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option is still accepted for backwards compatibility, but is deprecated.
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The following extended options are supported:
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.RS 1.2i
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.TP
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.BI encoding= encoding-name
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Enable the
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.I casefold
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feature in the super block and set
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.I encoding-name
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as the encoding to be used. If
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.I encoding-name
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is not specified, the encoding defined in
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.BR mke2fs.conf (5)
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is used.
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.TP
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.BI encoding_flags= encoding-flags
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Define parameters for file name character encoding operations. If a
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flag is not changed using this parameter, its default value is used.
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.I encoding-flags
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should be a comma-separated lists of flags to be enabled. To disable a
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flag, add it to the list with the prefix "no".
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The only flag that can be set right now is
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.I strict
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which means that invalid strings should be rejected by the file system.
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In the default configuration, the
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.I strict
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flag is disabled.
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.TP
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.BI mmp_update_interval= interval
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Adjust the initial MMP update interval to
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.I interval
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seconds. Specifying an
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.I interval
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of 0 means to use the default interval. The specified interval must
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be less than 300 seconds. Requires that the
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.B mmp
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feature be enabled.
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.TP
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.BI stride= stride-size
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Configure the filesystem for a RAID array with
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.I stride-size
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filesystem blocks. This is the number of blocks read or written to disk
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before moving to the next disk, which is sometimes referred to as the
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.I chunk size.
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This mostly affects placement of filesystem metadata like bitmaps at
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.B mke2fs
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time to avoid placing them on a single disk, which can hurt performance.
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It may also be used by the block allocator.
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.TP
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.BI stripe_width= stripe-width
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Configure the filesystem for a RAID array with
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.I stripe-width
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filesystem blocks per stripe. This is typically stride-size * N, where
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N is the number of data-bearing disks in the RAID (e.g. for RAID 5 there is one
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parity disk, so N will be the number of disks in the array minus 1).
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This allows the block allocator to prevent read-modify-write of the
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parity in a RAID stripe if possible when the data is written.
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.TP
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.BI offset= offset
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Create the filesystem at an offset from the beginning of the device or
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file. This can be useful when creating disk images for virtual machines.
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.TP
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.BI resize= max-online-resize
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Reserve enough space so that the block group descriptor table can grow
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to support a filesystem that has
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.I max-online-resize
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blocks.
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.TP
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.B lazy_itable_init\fR[\fB= \fI<0 to disable, 1 to enable>\fR]
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If enabled and the uninit_bg feature is enabled, the inode table will
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not be fully initialized by
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.BR mke2fs .
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This speeds up filesystem
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initialization noticeably, but it requires the kernel to finish
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initializing the filesystem in the background when the filesystem is
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first mounted. If the option value is omitted, it defaults to 1 to
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enable lazy inode table zeroing.
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.TP
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.B lazy_journal_init\fR[\fB= \fI<0 to disable, 1 to enable>\fR]
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If enabled, the journal inode will not be fully zeroed out by
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.BR mke2fs .
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This speeds up filesystem initialization noticeably, but carries some
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small risk if the system crashes before the journal has been overwritten
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entirely one time. If the option value is omitted, it defaults to 1 to
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enable lazy journal inode zeroing.
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.TP
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.B no_copy_xattrs
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Normally
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.B mke2fs
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will copy the extended attributes of the files in the directory
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hierarchy specified via the (optional)
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.B \-d
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option. This will disable the copy and leaves the files in the newly
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created file system without any extended attributes.
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.TP
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.BI num_backup_sb= <0|1|2>
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If the
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.B sparse_super2
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file system feature is enabled this option controls whether there will
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be 0, 1, or 2 backup superblocks created in the file system.
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.TP
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.B packed_meta_blocks\fR[\fB= \fI<0 to disable, 1 to enable>\fR]
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Place the allocation bitmaps and the inode table at the beginning of the
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disk. This option requires that the flex_bg file system feature to be
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enabled in order for it to have effect, and will also create the journal
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at the beginning of the file system. This option is useful for flash
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devices that use SLC flash at the beginning of the disk.
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It also maximizes the range of contiguous data blocks, which
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can be useful for certain specialized use cases, such as supported
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Shingled Drives.
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.TP
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.BI root_owner [=uid:gid]
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Specify the numeric user and group ID of the root directory. If no UID:GID
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is specified, use the user and group ID of the user running \fBmke2fs\fR.
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In \fBmke2fs\fR 1.42 and earlier the UID and GID of the root directory were
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set by default to the UID and GID of the user running the mke2fs command.
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The \fBroot_owner=\fR option allows explicitly specifying these values,
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and avoid side-effects for users that do not expect the contents of the
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filesystem to change based on the user running \fBmke2fs\fR.
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.TP
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.B test_fs
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Set a flag in the filesystem superblock indicating that it may be
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mounted using experimental kernel code, such as the ext4dev filesystem.
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.TP
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.B discard
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Attempt to discard blocks at mkfs time (discarding blocks initially is useful
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on solid state devices and sparse / thin-provisioned storage). When the device
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advertises that discard also zeroes data (any subsequent read after the discard
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and before write returns zero), then mark all not-yet-zeroed inode tables as
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zeroed. This significantly speeds up filesystem initialization. This is set
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as default.
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.TP
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.B nodiscard
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Do not attempt to discard blocks at mkfs time.
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.TP
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.B quotatype
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Specify the which quota types (usrquota, grpquota, prjquota) which
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should be enabled in the created file system. The argument of this
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extended option should be a colon separated list. This option has
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effect only if the
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.B quota
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feature is set. The default quota types to be initialized if this
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option is not specified is both user and group quotas. If the project
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feature is enabled that project quotas will be initialized as well.
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.RE
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.TP
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.B \-F
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Force
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.B mke2fs
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to create a filesystem, even if the specified device is not a partition
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on a block special device, or if other parameters do not make sense.
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In order to force
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.B mke2fs
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to create a filesystem even if the filesystem appears to be in use
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or is mounted (a truly dangerous thing to do), this option must be
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specified twice.
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.TP
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.BI \-g " blocks-per-group"
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Specify the number of blocks in a block group. There is generally no
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reason for the user to ever set this parameter, as the default is optimal
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for the filesystem. (For administrators who are creating
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filesystems on RAID arrays, it is preferable to use the
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.I stride
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RAID parameter as part of the
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.B \-E
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option rather than manipulating the number of blocks per group.)
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This option is generally used by developers who
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are developing test cases.
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.IP
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If the bigalloc feature is enabled, the
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.B \-g
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option will specify the number of clusters in a block group.
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.TP
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.BI \-G " number-of-groups"
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Specify the number of block groups that will be packed together to
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create a larger virtual block group (or "flex_bg group") in an
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ext4 filesystem. This improves meta-data locality and performance
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on meta-data heavy workloads. The number of groups must be a power
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of 2 and may only be specified if the
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.B flex_bg
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filesystem feature is enabled.
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.TP
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.BI \-i " bytes-per-inode"
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Specify the bytes/inode ratio.
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.B mke2fs
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creates an inode for every
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.I bytes-per-inode
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bytes of space on the disk. The larger the
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.I bytes-per-inode
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ratio, the fewer inodes will be created. This value generally shouldn't
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be smaller than the blocksize of the filesystem, since in that case more
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inodes would be made than can ever be used. Be warned that it is not
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possible to change this ratio on a filesystem after it is created, so be
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careful deciding the correct value for this parameter. Note that resizing
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a filesystem changes the number of inodes to maintain this ratio.
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.TP
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.BI \-I " inode-size"
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Specify the size of each inode in bytes.
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The
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.I inode-size
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value must be a power of 2 larger or equal to 128. The larger the
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.I inode-size
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the more space the inode table will consume, and this reduces the usable
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space in the filesystem and can also negatively impact performance.
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It is not
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possible to change this value after the filesystem is created.
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.IP
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In kernels after 2.6.10 and some
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earlier vendor kernels it is possible to utilize inodes larger than
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128 bytes to store
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extended attributes for improved performance.
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Extended attributes
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stored in large inodes are not visible with older kernels, and such
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filesystems will not be mountable with 2.4 kernels at all.
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.IP
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The default inode size is controlled by the
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.BR mke2fs.conf (5)
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file. In the
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.B mke2fs.conf
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file shipped with e2fsprogs, the default inode size is 256 bytes for
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most file systems, except for small file systems where the inode size
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will be 128 bytes.
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.TP
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.B \-j
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Create the filesystem with an ext3 journal. If the
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.B \-J
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option is not specified, the default journal parameters will be used to
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create an appropriately sized journal (given the size of the filesystem)
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stored within the filesystem. Note that you must be using a kernel
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which has ext3 support in order to actually make use of the journal.
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.TP
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.BI \-J " journal-options"
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Create the ext3 journal using options specified on the command-line.
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Journal options are comma
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separated, and may take an argument using the equals ('=') sign.
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The following journal options are supported:
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.RS 1.2i
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.TP
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.BI size= journal-size
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Create an internal journal (i.e., stored inside the filesystem) of size
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.I journal-size
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megabytes.
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The size of the journal must be at least 1024 filesystem blocks
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(i.e., 1MB if using 1k blocks, 4MB if using 4k blocks, etc.)
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and may be no more than 10,240,000 filesystem blocks or half the total
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file system size (whichever is smaller)
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.TP
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.BI location =journal-location
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Specify the location of the journal. The argument
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.I journal-location
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can either be specified as a block number, or if the number has a units
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suffix (e.g., 'M', 'G', etc.) interpret it as the offset from the
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beginning of the file system.
|
|
@JDEV@.TP
|
|
@JDEV@.BI device= external-journal
|
|
@JDEV@Attach the filesystem to the journal block device located on
|
|
@JDEV@.IR external-journal .
|
|
@JDEV@The external
|
|
@JDEV@journal must already have been created using the command
|
|
@JDEV@.IP
|
|
@JDEV@.B mke2fs -O journal_dev
|
|
@JDEV@.I external-journal
|
|
@JDEV@.IP
|
|
@JDEV@Note that
|
|
@JDEV@.I external-journal
|
|
@JDEV@must have been created with the
|
|
@JDEV@same block size as the new filesystem.
|
|
@JDEV@In addition, while there is support for attaching
|
|
@JDEV@multiple filesystems to a single external journal,
|
|
@JDEV@the Linux kernel and
|
|
@JDEV@.BR e2fsck (8)
|
|
@JDEV@do not currently support shared external journals yet.
|
|
@JDEV@.IP
|
|
@JDEV@Instead of specifying a device name directly,
|
|
@JDEV@.I external-journal
|
|
@JDEV@can also be specified by either
|
|
@JDEV@.BI LABEL= label
|
|
@JDEV@or
|
|
@JDEV@.BI UUID= UUID
|
|
@JDEV@to locate the external journal by either the volume label or UUID
|
|
@JDEV@stored in the ext2 superblock at the start of the journal. Use
|
|
@JDEV@.BR dumpe2fs (8)
|
|
@JDEV@to display a journal device's volume label and UUID. See also the
|
|
@JDEV@.B -L
|
|
@JDEV@option of
|
|
@JDEV@.BR tune2fs (8).
|
|
.RE
|
|
@JDEV@.IP
|
|
@JDEV@Only one of the
|
|
@JDEV@.BR size " or " device
|
|
@JDEV@options can be given for a filesystem.
|
|
.TP
|
|
.BI \-l " filename"
|
|
Read the bad blocks list from
|
|
.IR filename .
|
|
Note that the block numbers in the bad block list must be generated
|
|
using the same block size as used by
|
|
.BR mke2fs .
|
|
As a result, the
|
|
.B \-c
|
|
option to
|
|
.B mke2fs
|
|
is a much simpler and less error-prone method of checking a disk for bad
|
|
blocks before formatting it, as
|
|
.B mke2fs
|
|
will automatically pass the correct parameters to the
|
|
.B badblocks
|
|
program.
|
|
.TP
|
|
.BI \-L " new-volume-label"
|
|
Set the volume label for the filesystem to
|
|
.IR new-volume-label .
|
|
The maximum length of the
|
|
volume label is 16 bytes.
|
|
.TP
|
|
.BI \-m " reserved-blocks-percentage"
|
|
Specify the percentage of the filesystem blocks reserved for
|
|
the super-user. This avoids fragmentation, and allows root-owned
|
|
daemons, such as
|
|
.BR syslogd (8),
|
|
to continue to function correctly after non-privileged processes are
|
|
prevented from writing to the filesystem. The default percentage
|
|
is 5%.
|
|
.TP
|
|
.BI \-M " last-mounted-directory"
|
|
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 filesystem should be mounted.
|
|
.TP
|
|
.B \-n
|
|
Causes
|
|
.B mke2fs
|
|
to not actually create a filesystem, but display what it
|
|
would do if it were to create a filesystem. This can be used to
|
|
determine the location of the backup superblocks for a particular
|
|
filesystem, so long as the
|
|
.B mke2fs
|
|
parameters that were passed when the
|
|
filesystem was originally created are used again. (With the
|
|
.B \-n
|
|
option added, of course!)
|
|
.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 " creator-os"
|
|
Overrides the default value of the "creator operating system" field of the
|
|
filesystem. The creator field is set by default to the name of the OS the
|
|
.B mke2fs
|
|
executable was compiled for.
|
|
.TP
|
|
.B "\-O \fR[^]\fIfeature\fR[,...]"
|
|
Create a filesystem with the given features (filesystem options),
|
|
overriding the default filesystem options. The features that are
|
|
enabled by default are specified by the
|
|
.I base_features
|
|
relation, either in the
|
|
.I [defaults]
|
|
section in the
|
|
.B /etc/mke2fs.conf
|
|
configuration file,
|
|
or in the
|
|
.I [fs_types]
|
|
subsections for the usage types as specified by the
|
|
.B \-T
|
|
option, further modified by the
|
|
.I features
|
|
relation found in the
|
|
.I [fs_types]
|
|
subsections for the filesystem and usage types. See the
|
|
.BR mke2fs.conf (5)
|
|
manual page for more details.
|
|
The filesystem type-specific configuration setting found in the
|
|
.I [fs_types]
|
|
section will override the global default found in
|
|
.IR [defaults] .
|
|
.sp
|
|
The filesystem feature set will be further edited
|
|
using either the feature set specified by this option,
|
|
or if this option is not given, by the
|
|
.I default_features
|
|
relation for the filesystem type being created, or in the
|
|
.I [defaults]
|
|
section of the configuration file.
|
|
.sp
|
|
The filesystem feature set is comprised of a list of features, separated
|
|
by commas, that are to be enabled. To disable a feature, simply
|
|
prefix the feature name with a caret ('^') character.
|
|
Features with dependencies will not be removed successfully.
|
|
The pseudo-filesystem feature "none" will clear all filesystem features.
|
|
.TP
|
|
For more information about the features which can be set, please see
|
|
the manual page
|
|
.BR ext4 (5).
|
|
.TP
|
|
.B \-q
|
|
Quiet execution. Useful if
|
|
.B mke2fs
|
|
is run in a script.
|
|
.TP
|
|
.BI \-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.
|
|
.TP
|
|
.B \-S
|
|
Write superblock and group descriptors only. This is an extreme
|
|
measure to be taken only in the very unlikely case that all of
|
|
the superblock and backup superblocks are corrupted, and a last-ditch
|
|
recovery method is desired by experienced users. 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. Due to the wide
|
|
variety of possible options to
|
|
.B mke2fs
|
|
that affect the on-disk layout, it is critical to specify exactly
|
|
the same format options, such as blocksize, fs-type, feature flags, and
|
|
other tunables when using this option, or the filesystem will be further
|
|
corrupted. In some cases, such as filesystems that have been resized,
|
|
or have had features enabled after format time, it is impossible to
|
|
overwrite all of the superblocks correctly, and at least some filesystem
|
|
corruption will occur. It is best to run this on a full copy of the
|
|
filesystem so other options can be tried if this doesn't work.
|
|
.\" .TP
|
|
.\" .BI \-t " test"
|
|
.\" Check the device for bad blocks before creating the file system
|
|
.\" using the specified test.
|
|
.TP
|
|
.BI \-t " fs-type"
|
|
Specify the filesystem type (i.e., ext2, ext3, ext4, etc.) that is
|
|
to be created.
|
|
If this option is not specified,
|
|
.B mke2fs
|
|
will pick a default either via how
|
|
the command was run (for example, using a name of the form mkfs.ext2,
|
|
mkfs.ext3, etc.) or via a default as defined by the
|
|
.B /etc/mke2fs.conf
|
|
file. This option controls which filesystem options are used by
|
|
default, based on the
|
|
.B fstypes
|
|
configuration stanza in
|
|
.BR /etc/mke2fs.conf .
|
|
.sp
|
|
If the
|
|
.B \-O
|
|
option is used to explicitly add or remove filesystem options that
|
|
should be set in the newly created filesystem, the
|
|
resulting filesystem may not be supported by the requested
|
|
.IR fs-type .
|
|
(e.g., "\fBmke2fs \-t ext3 \-O extent /dev/sdXX\fR" will create a
|
|
filesystem that is not supported by the ext3 implementation as found in
|
|
the Linux kernel; and "\fBmke2fs \-t ext3 \-O ^has_journal /dev/hdXX\fR"
|
|
will create a filesystem that does not have a journal and hence will not
|
|
be supported by the ext3 filesystem code in the Linux kernel.)
|
|
.TP
|
|
.BI \-T " usage-type[,...]"
|
|
Specify how the filesystem is going to be used, so that
|
|
.B mke2fs
|
|
can choose optimal filesystem parameters for that use. The usage
|
|
types that are supported are defined in the configuration file
|
|
.BR /etc/mke2fs.conf .
|
|
The user may specify one or more usage types
|
|
using a comma separated list.
|
|
.sp
|
|
If this option is is not specified,
|
|
.B mke2fs
|
|
will pick a single default usage type based on the size of the filesystem to
|
|
be created. If the filesystem size is less than 3 megabytes,
|
|
.B mke2fs
|
|
will use the filesystem type
|
|
.IR floppy .
|
|
If the filesystem size is greater than or equal to 3 but less than
|
|
512 megabytes,
|
|
.BR mke2fs (8)
|
|
will use the filesystem type
|
|
.IR small .
|
|
If the filesystem size is greater than or equal to 4 terabytes but less than
|
|
16 terabytes,
|
|
.BR mke2fs (8)
|
|
will use the filesystem type
|
|
.IR big .
|
|
If the filesystem size is greater than or equal to 16 terabytes,
|
|
.BR mke2fs (8)
|
|
will use the filesystem type
|
|
.IR huge .
|
|
Otherwise,
|
|
.BR mke2fs (8)
|
|
will use the default filesystem type
|
|
.IR default .
|
|
.TP
|
|
.BI \-U " UUID"
|
|
Set the universally unique identifier (UUID) of the filesystem to
|
|
.IR UUID .
|
|
The format of the UUID is a series of hex digits separated by hyphens,
|
|
like this:
|
|
"c1b9d5a2-f162-11cf-9ece-0020afc76f16".
|
|
The
|
|
.I UUID
|
|
parameter may also be one of the following:
|
|
.RS 1.2i
|
|
.TP
|
|
.I clear
|
|
clear the filesystem UUID
|
|
.TP
|
|
.I random
|
|
generate a new randomly-generated UUID
|
|
.TP
|
|
.I time
|
|
generate a new time-based UUID
|
|
.RE
|
|
.TP
|
|
.B \-v
|
|
Verbose execution.
|
|
.TP
|
|
.B \-V
|
|
Print the version number of
|
|
.B mke2fs
|
|
and exit.
|
|
.TP
|
|
.BI \-z " undo_file"
|
|
Before overwriting a file system block, write the old contents of the block to
|
|
an undo file. This undo file can be used with e2undo(8) to restore the old
|
|
contents of the file system should something go wrong. If the empty string is
|
|
passed as the undo_file argument, the undo file will be written to a file named
|
|
mke2fs-\fIdevice\fR.e2undo in the directory specified via the
|
|
\fIE2FSPROGS_UNDO_DIR\fR environment variable or the \fIundo_dir\fR directive
|
|
in the configuration file.
|
|
|
|
WARNING: The undo file cannot be used to recover from a power or system crash.
|
|
.SH ENVIRONMENT
|
|
.TP
|
|
.B MKE2FS_SYNC
|
|
If set to non-zero integer value, its value is used to determine how often
|
|
.BR sync (2)
|
|
is called during inode table initialization.
|
|
.TP
|
|
.B MKE2FS_CONFIG
|
|
Determines the location of the configuration file (see
|
|
.BR mke2fs.conf (5)).
|
|
.TP
|
|
.B MKE2FS_FIRST_META_BG
|
|
If set to non-zero integer value, its value is used to determine first meta
|
|
block group. This is mostly for debugging purposes.
|
|
.TP
|
|
.B MKE2FS_DEVICE_SECTSIZE
|
|
If set to non-zero integer value, its value is used to determine logical
|
|
sector size of the
|
|
.IR device .
|
|
.TP
|
|
.B MKE2FS_DEVICE_PHYS_SECTSIZE
|
|
If set to non-zero integer value, its value is used to determine physical
|
|
sector size of the
|
|
.IR device .
|
|
.TP
|
|
.B MKE2FS_SKIP_CHECK_MSG
|
|
If set, do not show the message of filesystem automatic check caused by
|
|
mount count or check interval.
|
|
.SH AUTHOR
|
|
This version of
|
|
.B mke2fs
|
|
has been written by Theodore Ts'o <tytso@mit.edu>.
|
|
.SH AVAILABILITY
|
|
.B mke2fs
|
|
is part of the e2fsprogs package and is available from
|
|
http://e2fsprogs.sourceforge.net.
|
|
.SH SEE ALSO
|
|
.BR mke2fs.conf (5),
|
|
.BR badblocks (8),
|
|
.BR dumpe2fs (8),
|
|
.BR e2fsck (8),
|
|
.BR tune2fs (8),
|
|
.BR ext4 (5)
|