Checksumming blocks? [was Re: the " 'official' point of view" expressedby kernelnewbies.org regarding reiser4 inclusion]

From: Russell Leighton
Date: Thu Aug 03 2006 - 19:20:40 EST



If the software (filesystem like ZFS or database like Berkeley DB) finds a mismatch for a checksum on a block read, then what?

Is there a recovery mechanism, or do you just be happy you know there is a problem (and go to backup)?

Thx

Matthias Andree wrote:

Berkeley DB can, since version 4.1 (IIRC), write checksums (newer
versions document this as SHA1) on its database pages, to detect
corruptions and writes that were supposed to be atomic but failed
(because you cannot write 4K or 16K atomically on a disk drive).


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