e2image - Save critical ext2/ext3/ext4 filesystem metadata to a file
e2image [ -rsI ] device image-file
The e2image program will save critical ext2, ext3, or ext4 filesystem metadata located on
device to a file specified by image-file. The image file may be examined by dumpe2fs and
debugfs, by using the -i option to those programs. This can assist an expert in recover-
ing catastrophically corrupted filesystems. In the future, e2fsck will be enhanced to be
able to use the image file to help recover a badly damaged filesystem.
If image-file is -, then the output of e2image will be sent to standard output, so that
the output can be piped to another program, such as gzip(1). (Note that this is currently
only supported when creating a raw image file using the -r option, since the process of
creating a normal image file currently requires random access to the file, which cannot be
done using a pipe. This restriction will hopefully be lifted in a future version of
It is a very good idea to create image files for all of filesystems on a system and save
the partition layout (which can be generated using the fdisk -l command) at regular inter-
vals --- at boot time, and/or every week or so. The image file should be stored on some
filesystem other than the filesystem whose data it contains, to ensure that this data is
accessible in the case where the filesystem has been badly damaged.
To save disk space, e2image creates the image file as a sparse file. Hence, if the image
file needs to be copied to another location, it should either be compressed first or
copied using the --sparse=always option to the GNU version of cp.
The size of an ext2 image file depends primarily on the size of the filesystems and how
many inodes are in use. For a typical 10 gigabyte filesystem, with 200,000 inodes in use
out of 1.2 million inodes, the image file will be approximately 35 megabytes; a 4 gigabyte
filesystem with 15,000 inodes in use out of 550,000 inodes will result in a 3 megabyte
image file. Image files tend to be quite compressible; an image file taking up 32
megabytes of space on disk will generally compress down to 3 or 4 megabytes.
RESTORING FILESYSTEM METADATA USING AN IMAGE FILE
The -I option will cause e2image to install the metadata stored in the image file back to
the device. It can be used to restore the filesystem metadata back to the device in
WARNING!!!! The -I option should only be used as a desperation measure when other alter-
natives have failed. If the filesystem has changed since the image file was created, data
will be lost. In general, you should make a full image backup of the filesystem first, in
case you wish to try other recovery strategies afterwards.
RAW IMAGE FILES
The -r option will create a raw image file instead of a normal image file. A raw image
file differs from a normal image file in two ways. First, the filesystem metadata is
placed in the proper position so that e2fsck, dumpe2fs, debugfs, etc. can be run directly
on the raw image file. In order to minimize the amount of disk space consumed by a raw
image file, the file is created as a sparse file. (Beware of copying or compress-
ing/decompressing this file with utilities that don't understand how to create sparse
files; the file will become as large as the filesystem itself!) Secondly, the raw image
file also includes indirect blocks and directory blocks, which the standard image file
does not have, although this may change in the future.
Raw image files are sometimes used when sending filesystems to the maintainer as part of
bug reports to e2fsprogs. When used in this capacity, the recommended command is as fol-
lows (replace hda1 with the appropriate device):
e2image -r /dev/hda1 - | bzip2 > hda1.e2i.bz2
This will only send the metadata information, without any data blocks. However, the file-
names in the directory blocks can still reveal information about the contents of the
filesystem that the bug reporter may wish to keep confidential. To address this concern,
the -s option can be specified. This will cause e2image to scramble directory entries and
zero out any unused portions of the directory blocks before writing the image file. How-
ever, the -s option will prevent analysis of problems related to hash-tree indexed direc-
e2image was written by Theodore Ts'o (email@example.com).
e2image is part of the e2fsprogs package and is available from http://e2fsprogs.source-
E2fsprogs version 1.41.14 December 2010 E2IMAGE(8)