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2 Virtual Connect Domains in Stacked VC Configuration

 
cindyparks
Occasional Advisor

2 Virtual Connect Domains in Stacked VC Configuration

We're looking at stacking VC flex10 modules in 2 c7000 enclosures using cx4 cables. Then creating 2 separate VC Domains - domain 1 is the interconnects in bay1 of both enclosures with enclosure 1 as master, domain 2 is the interconnects in bay2 of both enclosures with enclosure 2 as master. The crosslink connections will be turned off and uplinks will be from bay 1 enclosure 1 and bay 2 enclosure 2. Is anyone out there doing this?
3 REPLIES
David Claypool
Honored Contributor

Re: 2 Virtual Connect Domains in Stacked VC Configuration

No, an enclosure cannot be split into 2 domains. See the VC Stacking Cookbook for supported configurations. Even if it were to work, your plan above introduces many points of failure (i.e. turning off crosslinks means no protection from upstream switch failure).
cindyparks
Occasional Advisor

Re: 2 Virtual Connect Domains in Stacked VC Configuration

Thanks for the response. Is it possible to stack the enclosures using cx4 cables so that traffic can stay in the enclosures, where appropriate, but have the enclosures in separate vc domains? requirements
1. keep intrablade communication local to the enclosures
2. if one enclosure goes completely offline, make vc config changes to the enclosure that remains operational.

Thanks for your help.
The Brit
Honored Contributor

Re: 2 Virtual Connect Domains in Stacked VC Configuration

Hi Cindy,

You really only have two options here.

1. Stack the two enclosures into a single VC domain. In this case, all profiles, vLANs, Uplinksets and SANs are unique and can be assigned to any server or bay in either enclosure.

2. The two enclosures are set up as two separate VC domains, where each enclosure represents one domain. In this case, all of the VC objects (profiles etc.) are restricted to the blades/bays in a single enclosure.

Communication between Blades within the same enclosure will normally travel out to the external switch, and then back, just because of the network setup, however, communication can be kept within the domain for situations where this is appropriate, e.g. cluster heartbeats, etc. Check out "Private Networks", but beware, the dehscription is the opposite to what you think.

I would not recommend that you try to split the enclosure Left side from Right side. The failover and redundancy design is based on a kind of Left/Right symmetry. For example, NIC teaming on individual servers should be set up using ports on say, module 1 and module 2, NOT on Module 1 and Module 3, because again for example, when doing FW upgrades the procedure will never take both modules 1 & 2 offline at the same time, however there is no such guarantee for modules 1 & 3.

If you use 1 & 2 for your NIC teaming, you will always have one of the modules online and available, even during FW upgrades. If you use 1 & 3, you might have both modules down, and hence your servers will probably go down.

HTH

Dave.