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

[Luca Berra <bluca comedia it>]

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 comedia it
       Communication Media & Services S.r.l.
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