E2IMAGE(8)						      System Manager's Manual							E2IMAGE(8)

NAME

       e2image - Save critical ext2/ext3/ext4 filesystem metadata to a file

SYNOPSIS

       e2image [ -rsI ] device image-file

DESCRIPTION

       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 recovering cat-
       astrophically  corrupted filesystems.  In the future, e2fsck will be enhanced to be able to use the image file to help recover a badly dam-
       aged 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 e2image.)

       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 intervals --- 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  filesys-
       tem  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 emergency situations.

       WARNING!!!!  The -I option should only be used as a desperation measure when other alternatives 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 compressing/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 follows (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 filenames 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.  However, the -s option will prevent analysis of problems related to hash-tree indexed directories.

AUTHOR

       e2image was written by Theodore Ts'o (tytso@mit.edu).

AVAILABILITY

       e2image is part of the e2fsprogs package and is available from http://e2fsprogs.sourceforge.net.

SEE ALSO

       dumpe2fs(8), debugfs(8)

E2fsprogs version 1.41.14					   December 2010							E2IMAGE(8)