On Tue Dec 08, 2009 at 09:01:23PM +0800, hank peng wrote:
> Hi, all:
> As we know, when a raid5 array is created, recovery will be going on
> which involves some read, one xor and one write. Since there is no
> real data in the disk at the time, besides, if I am willing to wait
> for recovery to complete and then use this raid5, how about adding
> support for a fast recovery method? Right now, what is in my mind is
> zero all disks which belong to this raid5. I think it will increase
> raid5 recovery speed when created and decrease CPU usage, since all
> zero is also XORed.
> What do raid developers think?
>
It'll decrease CPU usage but increase I/O - you're now needing to write
to all disks. Most systems will be I/O limited rather than CPU limited,
so the current approach works better. If you want to zero the disks
then do this before creating the array - you can then use --assume-clean
to skip the resync process.
Cheers,
Robin
--
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( ' } | Robin Hill <robin@xxxxxxxxxxxxxxx> |
/ / ) | Little Jim says .... |
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