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Why 8 ATTO bridges? Fabric Metrocluster with SAS stacks

gmilazzoitag
16,701 Views

Looking and reading at documentation regarding usage of ATTO SAS-FC bridge on Metrocluster I've always read about the need to have 4 bridges (as in the pic here) to connect and double the path to the stack SAS up to completation of one of this stack (seven DS4243 shelves).

I should setup a fabric MC where I will use both SAS and SATA disks in my DS4243 shelves: exactly as in the pic with one site with both 1xSAS+1xSATA shelves and the second site only with 1xSAS.

It now happens that configuring in PE/CE the needed hardware it give me EIGHT bridges for somewhere somebody says that this is best practice to have separate stack for SAS and SATA...what?!? This violates the principle that the SAS backend can do: a multiplexed one of four 3 Gbps links each

As far I know a stack SAS can be formed by both SAS and SATA disks mixing the DS4243 (up to ten shelves) and the ATTO manual too repeat this. No issue at all.

Why should my customer but other 4 ATTO bridges (9000 € each price list!)?

Regards

22 REPLIES 22

thomas_glodde
2,870 Views

yep, as i posted above you have 1 crossover point only anyway if rackspace Permits.

still, as of today, netapp quotation tool adds 8 bridges when going for sas and sata shelves and you manualy have to remove 4 of these to get a decent price.

radek_kubka
2,871 Views

Funnily enough, now the quoting tool specs 4 ATTO bridges & there is no option to increase it, even if two different types of shelves are attached.

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