Re: "Readonly" entry in your TODO list

[Patrik Jonsson <patrik@ucolick.org>]

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Steve Haehnichen wrote:
> Halfway through rebuilding, it found a read error on one drive!  This
> isn't shouldn't have been surprising, since some of the data is two
> years old had not been read in some time.
...
> Anyway, just a vote here for readonly assembly.  The second one on
> your todo list: "don't kick drives on read errors" would have probably
> been useful as well.
...
> The lesson I learned is that it's good hygiene to simply read all data
> on the drives now and then to 'prompt' any drive failures before there
> exists more than one at a time.  I intend to 'dd' read all of /dev/md0
> once a week or so in the background, in addition to the smartctl tests
> which did not detect this.

As someone who has been hit by this in the past, too, I'd like to
emphasize that
1. The raid5 read error correction works!
2. The raid5 "check" mode is very useful as a data exerciser. It's
running once a week as a cron job on my machine.

With these two features, my raid5 drive kicks have dropped to zilch.
(Small number statistics, but still...) If I were you, I'd update to a
kernel which supports this asap.

cheers,

/Patrik




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