2 .\" Copyright 2001 by Theodore Ts'o. All Rights Reserved.
3 .\" This file may be copied under the terms of the GNU Public License.
5 .TH E2IMAGE 8 "@E2FSPROGS_MONTH@ @E2FSPROGS_YEAR@" "E2fsprogs version @E2FSPROGS_VERSION@"
7 e2image \- Save critical ext2/ext3 filesystem data to a file
18 program will save critical filesystem data on the ext2 filesystem located on
20 to a file specified by
22 The image file may be examined by
28 option to those programs. This can be used by an expert in assisting
29 the recovery of catastrophically corrupted filesystems. In the future,
30 e2fsck will be enhanced to be able to use the image file to help
31 recover a badly damaged filesystem.
35 is -, then the output of
37 will be sent to standard output, so that the output can be piped to
38 another program, such as
40 (Note that is currently only supported when
41 creating a raw image file using the
43 option, since the process of creating a normal image file currently
44 requires random-access access to the file, which can not be done using a
45 pipe. This restriction will hopefully be lifted in a future version of
50 option will create a raw image file instead of a normal image file.
51 A raw image file differs
52 from a normal image file in two ways. First, the filesystem metadata is
53 placed in the proper position so that e2fsck, dumpe2fs, debugfs,
54 etc. can be run directly on the raw image file. In order to minimize
55 the amount of disk space consumed by a raw image file, the file is
56 created as a sparse file. (Beware of copying or
57 compressing/decompressing this file with utilities that don't understand
58 how to create sparse files; the file will become as large as the
59 filesystem itself!) Secondly, the raw image file also includes indirect
60 blocks and data blocks, which the current image file does not have,
61 although this may change in the future.
63 It is a very good idea to periodically (at boot time and
64 every week or so) to create image files for all of
65 filesystems on a system, as well as saving the partition
66 layout (which can be generated using the using
68 command). Ideally the image file should be stored on some filesystem
70 the filesystem whose data it contains, to ensure that its data is
71 accessible in the case where the filesystem has been badly damaged.
75 creates the image file as a sparse file.
76 Hence, if the image file
77 needs to be copied to another location, it should
78 either be compressed first or copied using the
80 option to GNU version of
83 The size of an ext2 image file depends primarily on the size of the
84 filesystems and how many inodes are in use. For a typical 10 gigabyte
85 filesystem, with 200,000 inodes in use out of 1.2 million inodes, the
86 image file be approximately 35 megabytes; a 4 gigabyte filesystem with
87 15,000 inodes in use out of 550,000 inodes will result in a 3 megabyte
88 image file. Image files tend to be quite
89 compressible; an image file taking up 32 megabytes of space on
90 disk will generally compress down to 3 or 4 megabytes.
94 was written by Theodore Ts'o (tytso@mit.edu).
97 is part of the e2fsprogs package and is available from anonymous
98 http://e2fsprogs.sourceforge.net.