.\"
.TH MKE2FS 8 "@E2FSPROGS_MONTH@ @E2FSPROGS_YEAR@" "E2fsprogs version @E2FSPROGS_VERSION@"
.SH NAME
-mke2fs \- create an ext2/3 filesystem
+mke2fs \- create an ext2/ext3 filesystem
.SH SYNOPSIS
.B mke2fs
[
.I bytes-per-inode
]
[
+.B \-I
+.I inode-size
+]
+[
.B \-j
]
[
.I fs-revision-level
]
[
-.B \-R
-.I raid-options
+.B \-E
+.I extended-options
]
[
.B \-v
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 hueristically determined by the file system size and
+block-size is heuristically determined by the file system size and
the expected usage of the filesystem (see the
.B \-T
option). If
.I block-size
-is negative, then mke2fs will use hueristics to determine the
+is negative, then
+.B mke2fs
+will use heuristics to determine the
appropriate block size, with the constraint that the block size will be
at least
.I block-size
.TP
.B \-c
Check the device for bad blocks before creating the file system. If
-this option is specified twice, then a slower, destructive, read-write
+this option is specified twice, then a slower, read-write
test is used instead of a fast read-only test.
.TP
+.BI \-E " extended-options"
+Set extended options for the filesystem. Extended options are comma
+separated, and may take an argument using the equals ('=') sign. The
+.B -E
+option used to be
+.B -R
+in earlier versions of
+.BR mke2fs .
+The
+.B -R
+option is still accepted for backwards compatibility. The
+following extended options are supported:
+.RS 1.2i
+.TP
+.BI stride= stride-size
+Configure the filesystem for a RAID array with
+.I stride-size
+filesystem blocks. This is the number of blocks read or written to disk
+before moving to next disk. This mostly affects placement of filesystem
+metadata like bitmaps at
+.BR mke2fs (2)
+time to avoid placing them on a single disk, which can hurt the performanace.
+It may also be used by block allocator.
+.TP
+.BI stripe-width= stripe-width
+Configure the filesystem for a RAID array with
+.I stripe-width
+filesystem blocks per stripe. This is typically be stride-size * N, where
+N is the number of data disks in the RAID (e.g. RAID 5 N+1, RAID 6 N+2).
+This allows the block allocator to prevent read-modify-write of the
+parity in a RAID stripe if possible when the data is written.
+.TP
+.BI resize= max-online-resize
+Reserve enough space so that the block group descriptor table can grow
+to support a filesystem that has max-online-resize blocks.
+.TP
+.B test_fs
+Set a flag in the filesystem superblock indicating that it may be
+mounted using experimental kernel code, such as the ext4dev filesystem.
+.RE
+.TP
.BI \-f " fragment-size"
Specify the size of fragments in bytes.
.TP
.B \-F
Force
.B mke2fs
-to run, even if the specified device is not a
-block special device, or appears to be mounted.
+to create a filesystem, even if the specified device is not a partition
+on a block special device, or if other parameters do not make sense.
+In order to force
+.B mke2fs
+to create a filesystem even if the filesystem appears to be in use
+or is mounted (a truly dangerous thing to do), this option must be
+specified twice.
.TP
.BI \-g " blocks-per-group"
Specify the number of blocks in a block group. There is generally no
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 deciding the
correct value for this parameter.
+.TP
+.BI \-I " inode-size"
+Specify the size of each inode in bytes.
+.B mke2fs
+creates 256-byte inodes by default. In kernels after 2.6.10 and some
+earlier vendor kernels it is possible to utilize inodes larger than
+128-bytes to store
+extended attributes for improved performance. The
+.I inode-size
+value must be a power of two larger or equal to 128. The larger the
+.I inode-size
+the more space the inode table will consume, and this reduces the usable
+space in the filesystem and can also negatively impact performance.
+Extended attributes
+stored in large inodes are not visible with older kernels, and such
+filesystems will not be mountable with 2.4 kernels at all. It is not
+possible to change this value after the filesystem is created.
.TP
.B \-j
Create the filesystem with an ext3 journal. If the
@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
.B badblocks
program.
.TP
-.B \-L
-Set the volume label for the filesystem.
+.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 value defaults to 5%.
+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
.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.
+determine where the filesystem should be mounted.
.TP
.B \-n
causes mke2fs to not actually create a filesystem, but display what it
executable.
.TP
.B "\-O \fIfeature\fR[,...]"
-Create filesystem with given features (filesystem options). Features
-which are normally turned on by default may be disabled by prefixing the
-feature with a caret ('^') symbol.
-Currently, the
-.B sparse_super
-and
-.B filetype
-features are turned on by default when
-.B mke2fs
-is run on a system with Linux 2.2 or later (unless creator-os is set to
-the Hurd). Filesystems that may need to be mounted on pre-2.2 Linux or
-other kernels should be created with
-.B "\-O none"
-(or
-.B "\-r 0"
-for Linux 1.2) which will disable these features, even if
-.B mke2fs
-is run on a system which can support them.
+Create filesystem with given features (filesystem options), overriding
+the default filesystem options. The default features which are
+enabled by default are specified by the
+.I base_features
+relation, either in the
+.I [libdefaults]
+section in the
+.B /etc/mke2fs.conf
+configuration file, or in the subsection of the
+.I [fs_types]
+section for the filesystem type as specified by the
+.B -T
+option. The filesystem type-specific configuration setting found in
+the
+.I [fs_types]
+section will override the global default found in
+.IR [libdefaults] .
+.sp
+The filesystem feature set will be further edited
+using either the feature set specification specified by this option,
+or if this option is not specified, by the
+.I default_features
+relation for the filesystem type being created, or in the
+.I [libdefaults]
+section of the configuration file.
.sp
-The following filesystem options are supported:
+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. The
+pseudo-filesystem feature "none" will clear all filesystem features.
.RS 1.2i
.TP
+.B large_file
+Filesystem can contain files that are greater than 2GB. (Modern kernels
+set this feature automatically when a file > 2GB is created.)
+.TP
.B dir_index
Use hashed b-trees to speed up lookups in large directories.
.TP
@JDEV@must be created with the same
@JDEV@block size as the filesystems that will be using it.
.TP
+.B resize_inode
+Reserve space so the block group descriptor table may grow in the future.
+Useful for online resizing using
+.BR resize2fs .
+By default
+.B mke2fs
+will attempt to reserve enough space so that the
+filesystem may grow to 1024 times its initial size. This can be changed
+using
+.B resize
+extended option.
+.TP
.B sparse_super
Create a filesystem with fewer superblock backup copies
(saves space on large filesystems).
kernels only support revision 0 filesystems. The default is to
create revision 1 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. The
-following options are supported:
-.RS 1.2i
-.TP
-.BI stride= stripe-size
-Configure the filesystem for a RAID array with
-.I stripe-size
-filesystem blocks per stripe.
-.RE
-.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
.\" using the specified test.
.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 supported
-filesystem types are:
-.RS 1.2i
-.TP 1.2i
-news
-one inode per 4kb block
-.TP
-largefile
-one inode per megabyte
-.TP
-largefile4
-one inode per 4 megabytes
-.RE
+Specify how the filesystem is going to be used, so that
+.B mke2fs
+can choose optimal filesystem parameters for that use. The filesystem
+types that are can be supported are defined in the configuration file
+.BR /etc/mke2fs.conf (5).
+The default configuration file contains definitions for the filesystem
+types: small, floppy, news, largefile, and largefile4.
.TP
.B \-v
Verbose execution.
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),
git://git.whamcloud.com / tools / e2fsprogs.git / blobdiff