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

[Jorge Peixoto de Morais Neto]

On Thu, Nov 27, 2008 at 10:12 AM, Daniel Troeder <daniel@×××××××××.com> wrote:
> Am Mittwoch, den 26.11.2008, 15:26 +0100 schrieb Florian Philipp:
>> > 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 myself would add a textfile with md5sums for all files to the DVD so
>> you don't have to check them visually.
I have recently taken this decision too. Unfortunately I haven't done
so for some old backups (fortunately they still seem healthy)
> You can buy so called "archival grade" DVD-Rs that should work for 10-20
> years in a good environment. There are hugh differences between
> products. In germany you can buy very good ones from Verbatim for around
> 2€/disk.
This can be hard to find in my mid-sized Brazilian city. If I lived in
the mega-metropolis of São Paulo, this would be far easier. And thanks
very much for recommending Verbatim. I have heard of Taiyo Yuden, but
that would likely be far harder to find.

Speaking of md5sum/shasum, do you know some tool that adds data
redundancy? I heard dvddistaster does this, but I guess it is limited
to DVDs. It would be great fo find a general data redundancy tool. In
the moment, with the tools I know, the best I can do is store the
files twice, with md5sums/shasums to decide which version is correct.
By the way, it seems from my (limited) experience that even sha256sums
are IO-bound (even on my not-so-powerful Athlon XP 2600+), so it makes
sense to calculate sha256sums (as instead of md5sums) even it is
overkill. To be doubly sure, one can calculate sha256sums *and*
md5sums.