From: Theodore Ts'o <tytso@mit.edu>
Date: Thu, 3 May 2001 16:30:48 +0000 (+0000)
Subject: e2image.8.in:
X-Git-Tag: E2FSPROGS-1_20~64
X-Git-Url: https://git.whamcloud.com/?a=commitdiff_plain;h=0edb4d8504afc08c48ce7f30b670a2a7e27db7bc;p=tools%2Fe2fsprogs.git

e2image.8.in:
  Updates and clarifications to the manual page.
---

diff --git a/misc/e2image.8.in b/misc/e2image.8.in
index e9688c8..a43f827 100644
--- a/misc/e2image.8.in
+++ b/misc/e2image.8.in
@@ -10,14 +10,55 @@ e2image \- Save critical ext2 filesystem data to a file
 .I device
 .I image-file
 .SH DESCRIPTION
+The
 .B e2image
-will save critical filesystem data on the ext2 filesystem located on 
+program will save critical filesystem data on the ext2 filesystem located on 
 display or change the filesystem label on the ext2 filesystem located on
-.I device
-to a file.
+.I device  
+to a file specified by 
+.IR image-file .
+The image file may be examined by 
+.B dumpe2fs
+and
+.BR  debugfs ,
+by using the
+.B \-i
+option to those programs.  This can be used by an expert in assisting
+the recovery of 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.
+.PP
+It is a very good idea to periodically (at boot time and 
+every week or so) to create image files for all of
+filesystems on a system, as well as saving the partition
+layout (which can be generated using the using
+.B fdisk -l
+command).  Ideally the image file should be stored on some filesystem
+other that
+the filesystem whose data it contains, to ensure that its data is
+accessible in the case where the filesystem has been badly damaged.
+.PP
+To save disk space, 
+.B 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 
+.B \--sparse=always
+option to GNU version of 
+.BR cp .  
+.PP
+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 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; a sparse image file taking up 32 megabytes of space on
+disk will generally compress down to 3 or 4 megabytes.
 .PP
 .SH AUTHOR
-.B e2label 
+.B e2image 
 was written by Theodore Ts'o (tytso@mit.edu).
 .SH AVAILABILITY
 .B e2image