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On Sat, 29 Nov 2008 04:21:44 pm Jorge Peixoto de Morais Neto wrote: |
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> On Thu, Nov 27, 2008 at 10:12 AM, Daniel Troeder <daniel@×××××××××.com> |
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wrote: |
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> > Am Mittwoch, den 26.11.2008, 15:26 +0100 schrieb Florian Philipp: |
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> > You can buy so called "archival grade" DVD-Rs that should work for 10-20 |
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> > years in a good environment. There are hugh differences between |
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> > products. In germany you can buy very good ones from Verbatim for around |
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> > 2€/disk. |
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> |
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> This can be hard to find in my mid-sized Brazilian city. If I lived in |
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> the mega-metropolis of São Paulo, this would be far easier. And thanks |
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> very much for recommending Verbatim. I have heard of Taiyo Yuden, but |
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> that would likely be far harder to find. |
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> |
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> Speaking of md5sum/shasum, do you know some tool that adds data |
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> redundancy? I heard dvddistaster does this, but I guess it is limited |
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> to DVDs. It would be great fo find a general data redundancy tool. In |
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> the moment, with the tools I know, the best I can do is store the |
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> files twice, with md5sums/shasums to decide which version is correct. |
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Have a look at app-arch/par2cmdline ( http://parchive.sourceforge.net/ ). It |
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will create parity files for an arbitrary set of data files and you can |
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choose your level of redundency (from 0 = now redundency, just integrity |
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checking, up to 100%). Although expect your parity files to be on the order |
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of the percentage for size, i.e. 50% redundancy for some given files to take |
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about 50% of their size for the parity files). |
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The down side I find with the tool is that it doesn't currently support |
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directories. This isn't so bad for creating parity files, but during |
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checking/restore, the program expects all files to exist in the current |
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directory, despite which sub-dirs they were originally in. You can get around |
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this with a tar/rar/zip first, then calculate parities on the archive though. |
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> By the way, it seems from my (limited) experience that even sha256sums |
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> are IO-bound (even on my not-so-powerful Athlon XP 2600+), so it makes |
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> sense to calculate sha256sums (as instead of md5sums) even it is |
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> overkill. To be doubly sure, one can calculate sha256sums *and* |
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> md5sums. |
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