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    Command:

    e2image

    
    
    

    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
           catastrophically  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.
    
           When  saving  an e2image for debugging purposes, using either the -r or
           -Q options, the filesystem must be unmounted or be  mounted  read/only,
           in order for the image file to be in a consistent state.  This require-
           ment can be overridden using the -f option,  but  the  resulting  image
           file is very likely not going to be useful.
    
           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, or QCOW2 image 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 dam-
           aged.
    
           To save disk space, e2image creates the image file as a sparse file, or
           in QCOW2 format.  Hence, if the sparse 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.   This  does  not
           apply to the QCOW2 image, which is not sparse.
    
           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 com-
           press 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
           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 under-
           stand  how to create sparse files; the file will become as large as the
           filesystem itself!)  Secondly, the raw image file also  includes  indi-
           rect  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  infor-
           mation  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 prob-
           lems related to hash-tree indexed directories.
    
           Note that this will work even if you substitute "/dev/hda1" for another
           raw disk image, or QCOW2 image previously created by e2image.
    
    
    

    QCOW2 IMAGE FILES

           The  -Q  option  will create a QCOW2 image file instead of a normal, or
           raw image file.  A QCOW2 image contains all  the  information  the  raw
           image  does,  however  unlike the raw image it is not sparse. The QCOW2
           image minimize the amount of disk space by storing data in special for-
           mat  with  pack data closely together, hence avoiding holes while still
           minimizing size.
    
           In order to send filesystem to the maintainer as a part of  bug  report
           to e2fsprogs, use following commands (replace hda1 with the appropriate
           device):
    
                e2image -Q /dev/hda1 hda1.qcow2
                bzip2 -z hda1.qcow2
    
           This will only send the metadata information, without any data  blocks.
           However,  the filenames in the directory blocks can still reveal infor-
           mation 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  prob-
           lems related to hash-tree indexed directories.
           dumpe2fs(8), debugfs(8)
    
    
    

    E2fsprogs version 1.41.12 May 2010 E2IMAGE(8)

    
    
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