1E2IMAGE(8) System Manager's Manual E2IMAGE(8)
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6 e2image - Save critical ext2/ext3/ext4 filesystem metadata to a file
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9 e2image [ -rsI ] device image-file
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12 The e2image program will save critical ext2, ext3, or ext4 filesystem
13 metadata located on device to a file specified by image-file. The
14 image file may be examined by dumpe2fs and debugfs, by using the -i
15 option to those programs. This can assist an expert in recovering cat‐
16 astrophically corrupted filesystems. In the future, e2fsck will be
17 enhanced to be able to use the image file to help recover a badly dam‐
18 aged filesystem.
19 If image-file is -, then the output of e2image will be sent to standard
21 output, so that the output can be piped to another program, such as
22 gzip(1). (Note that this is currently only supported when creating a
23 raw image file using the -r option, since the process of creating a
24 normal image file currently requires random access to the file, which
25 cannot be done using a pipe. This restriction will hopefully be lifted
26 in a future version of e2image.)
27 It is a very good idea to create image files for all of filesystems on
29 a system and save the partition layout (which can be generated using
30 the fdisk -l command) at regular intervals --- at boot time, and/or
31 every week or so. The image file should be stored on some filesystem
32 other than the filesystem whose data it contains, to ensure that this
33 data is accessible in the case where the filesystem has been badly dam‐
34 aged.
35 To save disk space, e2image creates the image file as a sparse file.
37 Hence, if the image file needs to be copied to another location, it
38 should either be compressed first or copied using the --sparse=always
39 option to the GNU version of cp.
40 The size of an ext2 image file depends primarily on the size of the
42 filesystems and how many inodes are in use. For a typical 10 gigabyte
43 filesystem, with 200,000 inodes in use out of 1.2 million inodes, the
44 image file will be approximately 35 megabytes; a 4 gigabyte filesystem
45 with 15,000 inodes in use out of 550,000 inodes will result in a 3
46 megabyte image file. Image files tend to be quite compressible; an
47 image file taking up 32 megabytes of space on disk will generally com‐
48 press down to 3 or 4 megabytes.
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51 The -I option will cause e2image to install the metadata stored in the
52 image file back to the device. It can be used to restore the
53 filesystem metadata back to the device in emergency situations.
54 WARNING!!!! The -I option should only be used as a desperation measure
56 when other alternatives have failed. If the filesystem has changed
57 since the image file was created, data will be lost. In general, you
58 should make a full image backup of the filesystem first, in case you
59 wish to try other recovery strategies afterwards.
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62 The -r option will create a raw image file instead of a normal image
63 file. A raw image file differs from a normal image file in two ways.
64 First, the filesystem metadata is placed in the proper position so that
65 e2fsck, dumpe2fs, debugfs, etc. can be run directly on the raw image
66 file. In order to minimize the amount of disk space consumed by a raw
67 image file, the file is created as a sparse file. (Beware of copying
68 or compressing/decompressing this file with utilities that don't under‐
69 stand how to create sparse files; the file will become as large as the
70 filesystem itself!) Secondly, the raw image file also includes indi‐
71 rect blocks and directory blocks, which the standard image file does
72 not have, although this may change in the future.
73 Raw image files are sometimes used when sending filesystems to the
75 maintainer as part of bug reports to e2fsprogs. When used in this
76 capacity, the recommended command is as follows (replace hda1 with the
77 appropriate device):
78 e2image -r /dev/hda1 - | bzip2 > hda1.e2i.bz2
80 This will only send the metadata information, without any data blocks.
82 However, the filenames in the directory blocks can still reveal infor‐
83 mation about the contents of the filesystem that the bug reporter may
84 wish to keep confidential. To address this concern, the -s option can
85 be specified. This will cause e2image to scramble directory entries
86 and zero out any unused portions of the directory blocks before writing
87 the image file. However, the -s option will prevent analysis of prob‐
88 lems related to hash-tree indexed directories.
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91 e2image was written by Theodore Ts'o (tytso@mit.edu).
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94 e2image is part of the e2fsprogs package and is available from
95 http://e2fsprogs.sourceforge.net.
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98 dumpe2fs(8), debugfs(8)
99E2fsprogs version 1.41.12 May 2010 E2IMAGE(8)