Friday, 11 May 2007

Mine's bigger than yours - do we care?

Our resident storage anarchist has been vigorously defending DMX - here. It's all in response to discussions with Hu regarding whether USP is better than DMX. Or, should I say DMX-3 and Broadway (whoops, I mentioned the unmentionable, you'll have to shoot me now).

I have to say I enjoyed the technical detail of the exchanges and I hope there will be a lot more to come. Any insight into how to make what are very expensive storage subsystems work more effectively has to be a good thing.

But here's the rub. Do we care about how much faster DMX-3 is over USP? I doubt the differences are more than incremental and as I've both installed, configured and provisioned storage on 9980V/USP/8730/8830/DMX/DMX2/DMX3, I think I've enough practical experience to qualify it. (By the way, I loved StorArch's comment about how flexible BIN file changes are now. Well, they may be, but in reality I've found EMC cumbersome to release configuration changes).

Finally I'll get round to the point of this post; most large enterprise subsystems are of the same order of magnitude of performance. However I've yet to see any deployment where performance management is executed to such a degree that, hand on heart, the storage admins there can claim they sequeeze 100% efficient throughput. I'd make an estimate that things probably run 80% efficient, with the major bottlenecks being port layout, backend array layout and host configuration.

So the theoretical bantering on who is more performant than the other is moot; now, EMC, HDS or IBM, come up with a *self tuning* array then you've got a winner...

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