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On Tue, Jan 8, 2013 at 2:06 PM, Florian Philipp <lists@×××××××××××.net> wrote: |
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> Am 08.01.2013 18:35, schrieb Volker Armin Hemmann: |
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>> Am Dienstag, 8. Januar 2013, 08:27:51 schrieb Florian Philipp: |
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>>> Am 08.01.2013 00:20, schrieb Alan McKinnon: |
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>>>> On Mon, 07 Jan 2013 21:11:35 +0100 |
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>>>> |
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>>>> Florian Philipp <lists@×××××××××××.net> wrote: |
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>>>>> Hi list! |
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>>>>> |
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>>>>> I have a use case where I am seriously concerned about bit rot [1] |
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>>>>> and I thought it might be a good idea to start looking for it in my |
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>>>>> own private stuff, too. |
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>>> |
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>>> [...] |
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>>> |
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>>>>> [1] http://en.wikipedia.org/wiki/Bit_rot |
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> [...] |
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>>>> If you mean disk file corruption, then doing it file by file is a |
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>>>> colossal waste of time IMNSHO. You likely have >1,000,000 files. Are |
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>>>> you really going to md5sum each one daily? Really? |
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>>> |
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>>> Well, not daily but often enough that I likely still have a valid copy |
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>>> as a backup. |
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>> |
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>> and who guarantees that the backup is the correct file? |
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>> |
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> |
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> That's why I wanted to store md5sum (or sha2sums). |
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> |
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>> btw, the solution is zfs and weekly scrub runs. |
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>> |
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> |
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> Seems so. |
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> |
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And, while it's not exceptionally likely, there's always a possibility |
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that the checksum table, rather than the file being checked itself, is |
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the location of the corruption, meaning you have to verify that as |
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well when discrepancies occur. The likelihood of the perfect few bits |
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flipping to match the corrupted data with a corrupted hash, within the |
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time between checks, however, I would think is low enough to gamble on |
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never seeing it in a reasonable lifetime. |
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|
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-- |
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Poison [BLX] |
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Joshua M. Murphy |
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