[nflug] Verifying a cdrom image backup

[Daniel V]

Who has time to mess with restoring from lots of CD-ROM's ? I backup my data, and then if necessary, I'll just reinstall, then come back and restore my scripts, my email, etc... Just an idea, it might save you a lot of time.

Daniel


--- On Fri, 12/12/08, Christopher Hawkins <chawkins at bplinux.com> wrote:

> From: Christopher Hawkins <chawkins at bplinux.com>
> Subject: Re: [nflug] Verifying a cdrom image backup
> To: nflug at nflug.org
> Date: Friday, December 12, 2008, 9:37 AM
> http://www.mondorescue.org/
> 
> See above - it's an open source package that does
> exactly what you describe. I have used it before and I think
> there's an option in the menu interface to verify all
> data on all cds. Maybe you would be better off with their
> software and maybe not, but either way you might just
> download their code and see how they do verification.
> 
> Agree with Brad... The only way to know is to actually
> restore it and then compare. Maybe restore then rsync -avn
> original_dir/* restored_dir/
> 
> The -n option means don't transfer anything, just tell
> what would have been transferred. That will give you a file
> level comparison that would ignore differences in the
> underlying media, filesystem, whatever, and you could run it
> even with the restore on another machine or just with the
> .iso mounted. 
> 
> Chris
> 
> ----- Original Message -----
> From: "Joe" <josephj at main.nc.us>
> To: nflug at nflug.org
> Sent: Friday, December 12, 2008 2:39:30 AM GMT -05:00
> US/Canada Eastern
> Subject: [nflug] Verifying a cdrom image backup
> 
> I'm making image backups of my system in chunks that
> fit on cdroms.
> 
> I created files such as rootu001.iso, rootu002.iso, etc.
> using dump with
> an unmounted file system.
> Then, I used cdrecord to burn a CD which has a file called
> rootu001 ...
> on it.
> Next, I ran md5sum against each and they do not match.
> I did this twice (two cdroms).
> I did an ls -l of both files and the .iso file is somewhat
> larger than
> the one on the cdrom.  There were no error messages, etc.
> during the
> burn (using burnfree which is supported on the drive).  As
> far as I
> know, the cdrom drive is working fine.
> 
> I just ran a 15 cdrom backup that worked fine, but I
> realized afterwards
> that since the root file system was mounted, the backup was
> probably
> useless, so I recreated it using a livecd with the root
> unmounted. 
> That's the one I'm having trouble verifying now.
> 
> Am I doing something wrong?
> 
> How do I verify that what I wrote to the cdrom is identical
> to the image
> on disk and is completely readable - a reliable/restorable
> copy?
> 
> TIA
> 
> Joe
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