Re: Backup's to DVD
On Mon, 17 Mar 2014 09:57:07 +0100
andre@cyberh0me.net wrote:
> >> On Sun, 2014-03-16 at 16:54 -0500, Mr Queue wrote:
> >> > I already have a pair of backup servers in different physical
> >> > locations
> >>
> >> That's good. DVDs IMHO are useless as serious backup medias.
> >
> > Because?
> >
>
> for example lifetime of the media itself, problems to read on
> different kind of dvd drives and some other kind of Problems
Thanks Andre.
So far, I haven't had readability problems on old CDs and DVDs.
Blu-Rays seem a little squirrelly over time, but CDs and DVDs seem
readable for many years.
>
> there are so many reasons why enterprise companys never use dvd's as
> storage medium for their data
I think one of the big reasons enterprise backups avoid optical media
is shear size. With DVD max 4.7GB and Blu-Ray max 25GB, a bare metal
backup could involve a lot of time consuming media switching.
But look at the alternatives. Tape has *always* been iffy on
restorability, especially consumer grade tape devices.
Backing up to a 2TB, 2.5" Western Digital external disk, about $120.00
at Costco, is a real possibility, but:
1) If you're worried about long time readability, you don't want this,
because you're always going to be tempted to cannibalize old backups
to make room for new ones, rather than spending another $120.00.
2) Magnetic disks tend to stop working if not spun up at regular
intervals.
3) Magnetic disks can be (accidentally) erased. Not so with write-once
optical media.
4) Magnetic disks are very subject to electric destruction and physical
shock.
Then there's "cloud backup". This would theoretically be great if you
could trust the commercial entity to:
1) Carefully keep you backups for later use
2) Protect your backups from being viewed by others.
In practice, the only way I'd ever trust a cloud backup entity is if I
had alternative copies (which I would), and the backup I submitted to
them was GPG protected with maximum key size.
Also, if you're like me and have upload speeds of less than 1Mbit, it's
going to take forever to back up. And once again, for privacy reasons,
there's no way I'd let the backup system iteratively access the files
on my computer.
> however it depends how long you try to have this backup available and
> if you want to be sure you have a working backup
Exactly. In practice, I do these three things:
* Maintain my own, rsync driven, incremental backup server, as described
at http://www.troubleshooters.com/lpm/200609/200609.htm
* Back up from the backup server to Blu-Ray
* Back up from the backup server to Western Digital 2.5" drives
Thanks,
SteveT
Steve Litt * http://www.troubleshooters.com/
Troubleshooting Training * Human Performance
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