Messages in this thread | | | Date | Tue, 19 Jun 2007 13:51:36 -0700 (PDT) | From | david@lang ... | Subject | Re: limits on raid |
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On Tue, 19 Jun 2007, Lennart Sorensen wrote:
> On Mon, Jun 18, 2007 at 02:56:10PM -0700, david@lang.hm wrote: >> yes, I'm useing promise drive shelves, I have them configured to export >> the 15 drives as 15 LUNs on a single ID. >> >> I'm going to be useing this as a huge circular buffer that will just be >> overwritten eventually 99% of the time, but once in a while I will need to >> go back into the buffer and extract and process the data. > > I would guess that if you ran 15 drives per channel on 3 different > channels, you would resync in 1/3 the time. Well unless you end up > saturating the PCI bus instead. > > hardware raid of course has an advantage there in that it doesn't have > to go across the bus to do the work (although if you put 45 drives on > one scsi channel on hardware raid, it will still be limited).
I fully realize that the channel will be the bottleneck, I just didn't understand what /proc/mdstat was telling me. I thought that it was telling me that the resync was processing 5M/sec, not that it was writing 5M/sec on each of the two parity locations.
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