On Tuesday August 10, philip@xxxxxxxxxxxxxx wrote:
>
> Linux RAID *has* to have sort of way to force a parity resync. If it
> doesn't have one, it needs one. That's a glaring omission to make.
Well, you get what you pay for.....
The easiest way to force a resync would be to re-create the array.
- Note the exact order of the drives in the array, and the chunk size.
- Stop the array.
- Create the array with mdadm using --force. That bit is important.
mdadm --create /dev/mdX --level=5 --force --disks=whatever \
--chunksize=64k /dev/sda1 /dev/sdb1 .....
Remember the --force. If you don't have it, you will get a recovery
cycle that rebuilds one drive against the others rather than a resync
that checks and corrects parity.
This will recreate the array (almost) exactly as it currently is, but
it will not be marked 'clean', so a parity check-and-correct will
happen.
It should be fairly easy to add a --update=dirty option to
"mdadm --assemble"
to make that a bit easier. I might do that in a day or two (though
I might not).
Ofcourse, it would be really nice if you could just tell md to run a
resync pass. It's on my todo list, but it isn't the only thing.
Clean, well-designed, small patches gladly accepted.
NeilBrown
(don't forget the --force)
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