On Sep 15, 2009, at 2:12 PM, Majed B. wrote:
Well, just because the PCI-e 1x bus can do 250 MB/s, it doesn't mean that the Port Multiplier (PM) can reach that speed, hence me telling you to test the card itself with 1 disk to see its max speed, then add another and so on.
You didn't tell me, you told Drew. And I wasn't reporting test results I got in response to your instructions, these tests have already been done (and well more in fact). I was just relaying what I found on this card and this setup for Drew's benefit.
Some PMs can communicate with each other. Check the specification sheet to see if your PM can do that. If that's the case, keep your disks of one array connected to PMs of the same chip, and use the built-in ports of the motherboard for another array or just normal disks.
This is a test machine I built specifically for testing bare ports versus pm setups. I destroy and create new raid arrays on it all the time, and none of them are for real use, just benchmarking.
-- Doug Ledford <dledford@xxxxxxxxxx> GPG KeyID: CFBFF194 http://people.redhat.com/dledford InfiniBand Specific RPMS http://people.redhat.com/dledford/Infiniband
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