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Linux 2.6 - man page for e2image (linux section 8)

E2IMAGE(8)									       E2IMAGE(8)

       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.

       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 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.

       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 (tytso@mit.edu).

       e2image is part of the e2fsprogs package and is	available  from  http://e2fsprogs.source-

       dumpe2fs(8), debugfs(8)

E2fsprogs version 1.41.14		  December 2010 			       E2IMAGE(8)

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