Re: [gentoo-user] Re: [OT] filesystems

["Jorge Peixoto de Morais Neto" <please.no.spam.here@gmail.com>]

On Wed, Nov 26, 2008 at 12:26 PM, Florian Philipp
<lists@f_philipp.fastmail.net> wrote:
>> As for my photos, I can back all the collection to a single DVD (and
>> to a second one, since I keep hearing that DVD-Rs are unreliable), and
>> since I don't take new photos every week, this solution is fine.
>>
>
> A second DVD-R won't solve the problem because optical disks degrade over
> time and the second one will degrade just as fast as the first. What you
> need to do is to check the disks periodically (once a year is a good time
> frame).
I know DVD-Rs degrade, but it is unlikely they would fail at the same
time, so copying twice does significantly alleviate the problem
(AFAIK)
Once a year isn't overkill? Isn't once every two years fine?

> I myself would add a textfile with md5sums for all files to the DVD so you
> don't have to check them visually.
Sure. I am doing that since some time now. Unfortunately I didn't do
so for some old backups. But data DVD-Rs have a considerable amount of
correction code, and if the copy from DVD to hard disk proceeds
without a single error message, there is a quite good chance that the
files are good, right?
(If they were burnt correctly in the fist place, that is. The manual
of my DVD-RW drive warns that the burned disk should be checked before
being trusted as a backup, and even then it - as usual - disclaims all
warranties).