Re: Burning and mounting written BDs

[Thomas Schmitt]

Hi,

Kjetil Kjernsmo wrote:
> to start off, I have now complete the backups I wanted. :-)

\o/


> for completeness, I then went back to the discs I had given up, to see
> if I might be able to find more error messages in the logs when I mounted
> them.
> And to me my great surprise, they all mounted without a hitch!

Keep in mind that mountability does not necessarily mean readability of
all file content. mount(8) only needs a readable superblock and possibly
a readable root directory of the filesystem.

The bulk of the filesystem tree and all the data file content needs to
be checked by reading the entire disc. Either by xorriso -checkread or
by some archiver like tar(1) which traverses all branches of the tree and
reads all data file content.


> Which could indicate the drive was a bit weird...?

It is not decided yet whether the computer (including its operating
system) or the drive was to blame. xorriso -checkread was able to read
the first few MB of the medium when mount(8) reported failure. So it
seems possible that the block device layer of Linux had a stake in the
refusal. On the other hand i know of no such problem in Linux.

So we will have to wait until it happens again and hopefully find some
clue in the system logs. Therefore i propose to make a copy of the full
system log immediately after such a problem occured again. Then we can
discuss which parts of that log might give answers (and how to remove
any private information before showing it to me and the world).
I'm looking forward to your next yearly backup.


Have a nice day :)

Thomas