Re: Incremental CDR backups -- SOLVED

[lorian@fsavigny.de]

Hello Paul,

  > # Make image
  > mkisofs -r -o /tmp/cdimage /home/paulf/cdrom
  > # Test image
  > mount /tmp/cdimage -r -t iso9660 -o loop /cdrom
  > mc /cdrom

To do a more thourough and completely automatic check, I suggest you
say 'diff -rq /cdrom /home/paulf/cdrom'. This will, however, yield
errors for files which have not changed in future sessions (not in
this one, since it is the first).

  > umount /cdrom
  > # Actual burn
  > cdrecord -v -multi speed=4 dev=0,0 /tmp/cdimage
  > # Test CDR
  > mount -t iso9660 -o ro /dev/cdrom /cdrom
  > mc /cdrom

see above

  > Some notes: It is possible to determine if a disk has been burned before
  > by checking the results of cdrecord -multi dev=0,0. If empty, then so is
  > the disk. This would allow a script to determine which branch to take
  > (virgin or already burned). 

You seem to go down about the same path as I did :-) mine does exactly that.

  > Also in testing the above, I also note that sometimes the kernel
  > is dumb about what's on the CDR. Apparently, when testing the
  > image burned on the CDR from later sessions, Linux will sometimes
  > think nothing has changed from the last burn. It appears that if
  > you eject the disk, it usually resolves this problem. 

This is one suggestion I forgot - but still, I sometimes needed to put
the CD-R in a different drive to make the system recognise there was
something new on it.

I'll mail you the scripts in private. I hope I'll find the time to put
it on the Web and also add some documentation (currently, read the
file /usr/share/doc/flcdbackup/README.1st about the scattered state of the
documentation).

Needless to say, any criticism is welcomed.

Florian