Hello. We have a website backup that has to be recovered thanks to
webserver hard disk crash. However the person who burned the backup
seems to have done it wrong. This is what we investigated what most
likely have happened:
a. he have a DVD+R that has a session on it.
b. he created a backup iso image by merging that session:
$ genisoimage -C ... -M /dev/sr0 -o backup.iso website_backup/
c. he burnt the backup to a /different/ DVD+R that also had a session:
$ wodim dev=/dev/sr1 backup.iso
(or, might also have been "$ growisofs -M /dev/sr1=backup.iso" )
d. he happily labeled the DVD+R in /dev/sr1 as "website backup". no
double check. done.
Now, we have the DVD+R that was there in /dve/sr1 when he do step c,
because it is correctly labeled as website backup. I can dump
backup.iso by using this:
$ dd if=/dev/sr1 of=backup.iso bs=2048 count=155440 skip=1256096
where value of count and skip are found here
$ dvd+rw-mediainfo /dev/sr1 | grep -A 4 '.\[#2\]'
READ TRACK INFORMATION[#2]:
Track State: partial/complete
Track Start Address: 1256096*2KB
Free Blocks: 0*2KB
Track Size: 155440*2KB
We do not know which DVD+R was in /dev/sr0 when he do step b. There
are a few hundreds in stock. We can locate a dozen that might be if
really have to. The dumped backup.iso has the right size, that makes
me believe nothing merged from the previous session in step b are
important to me. In other words, backup.iso should contain all data I
need to recover the website.
However, reasonable to believe, I could not mount backup.iso:
# mount -o loop backup.iso /mnt/
mount: /dev/loop0: can't read superblock
My question is, is there a way to recover hierarchical file backup
from backup.iso, except all files and directories that refer to the
previous session, which we could not easily find and should not need?