[dm-devel] dm-multipath has great throughput but we'd like more!

[Luca Berra]

On Thu, May 18, 2006 at 08:44:14AM +0100, Bob Gautier wrote:
>The card is a 64-bit PCI-X, so I don't think the bus is the bottleneck,
>and anyway the vendor specifies a maximum throughput of 200Mbyte/s per
>card.
>
>The disk array does not appear to be the bottleneck because we get
>200Mbyte/s when we use *two* HBAs in load-balanced mode.
>
>The question is really about why we only see O(100Mbyte/s) with one HBA
>when we can achieve O(200MByte/s) with two cards, given that one card
>should be able to achieve that throughput.
>
>I don't think the method of producing the traffic (bonnie++ or something
>else) should be relevant but if it were that would be very interesting
>for the benchmark authors!
>
>The storage is an HDS 9980 (I think?)
i am not an expert with Hitachi storages,
anyway
does each hba map to a different controller on the storage?
do you have some statistics on disk usage from the storage side?

L.

-- 
Luca Berra -- bluca at comedia.it
        Communication Media & Services S.r.l.
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