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Re: changing raid level?
Manuel Bouyer writes:
> On Tue, Jan 27, 2009 at 01:23:37PM -0600, Greg Oster wrote:
> > [...]
> > For a RAID 1 set, the "parity unit" is simply the second disk, and
> > computing that parity requires no further computations.
> On a slow CPU the read+read+compare+write is killing the whole system
> (mostly the "compare" I think) with 90% of the cpu working on this.
> A simple read+write is much, much better on such a setup (the system
> is still useable while doing a raid1 reconstruct). It matters
> even on a fast CPU, when both disks are able to provide data at 180MB/s.
> The system is still useable but comptationnal tasks (esp. network
> encryption) is much, much slower.
What should happen here is that RAIDframe should have a tweakable
sysctl knob (or something) to adjust the rebuild rate. It's on the
TODO list, but has never reached any sort of priority level where
it's gotten done :(
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