Re: SUCESS!!! - was [Re: Progress report Re: Invoking ddrescue]

["Thomas Schmitt" <scdbackup@gmx.net>]

Hi,

Richard Owlett wrote:
> ddrescue has run to completion without _reported_ errors for all partitions
> of the drive. I understand that does *NOT* guarantee that the files are not
> corrupt.

A coarse test would be to mount the partitions and to let some archiver
crawl the tree to read the content of each data file.

Create a mount point for the partition to be tested:

  mkdir /mnt/partition

Then with each of the copied partition files /mnt/my_sdb6/my_sdc* do:

  mount -o loop,ro,nodev,noexec,nosuid /mnt/my_sdb6/my_sdc1 /mnt/partition

  tar cf - /mnt/partition | wc -c

  umount /mnt/partition

If tar does not report i/o errors and wc tells a plausible byte count,
then all might be well.

mounting has to be done as superuser, of course.
man 8 mount paragraph "Mount options for ntfs" says that you will have
to do the tar part as superuser, unless you assign it at mount time
to a less powerful user id. I read from the manual something like:
  -o loop,ro,nodev,noexec,nosuid,uid=NORMAL_USER_ID,umask=400
but have no ntfs to test whether this makes all file readable for the
desktop user of whom you obtained the number NORMAL_USER_ID by:
  echo $UID


Does somebody know an entertaining filter in Debian, which one could put
between tar and wc to see a progress counter ?


Not so easy to test:
- The file content may still be damaged on application level (e.g. zeros
  where other data should be).
- Important parts of the tree may be missing.


Have a nice day :)

Thomas