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On Tue, 8 Jan 2013 22:15:15 +0000 (UTC) |
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Grant Edwards <grant.b.edwards@×××××.com> wrote: |
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> IMO, having backup data _is_ very valuable, but regularly reading |
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> files and comparing them to backup copies isn't a useful way to detect |
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> failing media. |
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He doesn't suggest you compare the live data to a backup. He suggests |
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you compare the current checksum to the last known (presumed or |
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verified as good) checksum, and if they are different then deal with it. |
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"deal with it" likely involves a restore after some kind of verify |
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process. |
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I agree that comparing current data with a backup is pretty pointless - |
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you don't know which is the bad one if they differ. |
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ZFS is designed to deal with this problem by checksumming fs blocks |
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continually; it does this at the filesystem level, not at the disk |
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firmware level. Pity about the license incompatibility, it's a great fs. |
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-- |
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Alan McKinnon |
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alan.mckinnon@×××××.com |
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