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November 30th, 2017 18:00

SC5020 new install

Hi

I have a sc5020 (2 of them), with a iSCSI card on top of the normal io ports.

and a arista mlag switch for each chasis

Fault domains, currently I have

C1 

P1 -> top sw

P2 -> bottom sw

C2

p1 -> top sw

P2 -> bottom sw

My current fault doamins are

FD1 C1-p1 & C2-P2

FD2 C1-p2 & C2-p1

The dell guy who was installing was saying this is not a supported setup and that i can have

FD1 C1-p1 & C2-P1

FD2 C1-p2 & C2-p2

or

FD1 with all the 4 ports in there.

trying to find a best practise document for this.

I am thinking of going to 1 FD.  This is for a VMWare 5.5 env.  My presumption is that I have 1 discovery ip and that the hosts will attach to all 4 of the underling ports ?

and that packets sent will be round robined between the actual ports

115 Posts

December 1st, 2017 07:00

You want to have ports in the same switch to be in the same fault domain so what he recommended is correct.  

All SC Best Practices:

http://en.community.dell.com/techcenter/storage/w/wiki/5018.sc-series-technical-documents

SC & VMware Best Practices:

http://en.community.dell.com/techcenter/extras/m/white_papers/20441056

76 Posts

December 1st, 2017 10:00

Do you know why.

Because to me that means you have a single point of failure. if the switch dies you loose the fault domain, atleast if you cross p1 - p2 you remove the single point of failure

115 Posts

December 1st, 2017 11:00

Volumes live across Fault Domains not within a fault domain so there's no single point of failure.

76 Posts

December 3rd, 2017 20:00

So my experience with equa logics - which I am replacing with the compellents.

Is something like this.  Each path accepts IO. if a path fails - so if I loose a switch a FD and there fore a path will fail. IO will back up until such time as it registers as down.

In these circumstances, I see IO waits sky rocket on Linux VM's and affect long lived tcp session.

So I am attempting to make sure I don't have  a single point of failure. 

Not one has yet told me why my cross setup is bad / wrong. only that its not the current best practise.

76 Posts

December 6th, 2017 18:00

Doing a training course on SC.

Seems like the issue is I have a stacked / MLAG set of switches and its not really separate fabrics.

I'm going to move to 1 FD and 4 ports

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