2012-10-25 21:17, Timothy Coalson wrote:

On Thu, Oct 25, 2012 at 7:35 AM, Jim Klimov <jimkli...@cos.ru
<mailto:jimkli...@cos.ru>> wrote:

    If scrubbing works the way we "logically" expect it to, it
    should enforce validation of such combinations for each read
    of each copy of a block, in order to ensure that parity sectors
    are intact and can be used for data recovery if a plain sector
    fails. Likely, raidzN scrubs should show as compute-intensive
    tasks compared to similar mirror scrubs.

It should only be as compute intensive as writes - it can read the
userdata and parity sectors, ensure the userdata checksum matches
(reconstruct and do a fresh write in the rare cases it is not), and then
recalculate the parity sectors from the verified user sectors, and
compare them to the parity sectors it actually read.

Hmmm, that's another way to skin the cat, and it makes more sense ;)

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