[Date Prev][Date Next] [Thread Prev][Thread Next] [Date Index] [Thread Index]

Bug#189249: ITP: ddrescue -- Like dd, dd_rescue does copy data from one file or block device to another

Package: wnpp
Version: unavailable; reported 2003-04-16
Severity: wishlist

* Package name    : dd_rescue 
  Version         : 1.0.2
  Upstream Author : Kurt Garloff <kurt@garloff.de>
* URL             : http://www.garloff.de/kurt/linux/ddrescue/
* License         : GPL
  Description     : dd_rescue does copy data from one file or block device to another

>From homepage:

The latter three features make it suitable for rescuing data from a
medium with errors, i.e. a hard disk with some bad sectors.

* Imagine, one of your partitions is crashed, and as there are some
  hard errors, you don't want to write to this hard disk any more. Just
 getting all the data off it and retiring it seems to be suitable.
 However, you can't access the files, as the file system is damaged.
* Now, you want to copy the whole partition into a file. You burn it on
  CD-Rom, just to never loose it again. You can setup a loop device, and
  repair (fsck) it and hopefully are able to mount it.
* Copying this partition with normal Un*x tools like cat or dd will
  fail, as those tools abort on error. dd_rescue instead will try to read
  and if it fails, it will go on with the next sectors. The output file
  naturally will have holes in it, of course. You can write a log file, 
  to see, where all these errors are located.

* The data rate drops very low, when errors are encountered. If you
  interrupt the process of copying, you don't loose anything. You can
  just continue at any position later. The output file will just be
  filled in further and not truncated as with other Un*x tools.
* If you have one spot of bad sectors within the partition, it might be
  a good idea, to approach this spot from both sides. Reverse direction
  copy is your friend.

* The two block sizes are a performance optimization. Large block sizes
  result in superior performance, but in case of errors, you want to try
  to salvage every single sector. So hardbs is best be set to the
  hardware sector size (most often 512 bytes) and softbs to a large
  value, such as the default 16k.

It will be uploaded soon by my sponsor  Gerfried Fuchs<alfie!debian.org>.


-- System Information:
Debian Release: testing/unstable
Architecture: i386
Kernel: Linux matrix 2.4.18-bf2.4 #1 Son Apr 14 09:53:28 CEST 2002 i686
Locale: LANG=de_DE@euro, LC_CTYPE=de_DE@euro

   .~.     .~.
  / O \   / ^ \
 (|   |) /|   |\
 '\   /` `\   /`
   ^`^     ^`^	
   Ayman Negm
 gpg-Key: 0x63E8BE82

Reply to: