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vmware clusters and L2 Spanning

Server virtualization and coud computing are the driving forces behind the need to span a network's L2 domain. This is where TRILL comes into play. You get horizontal scale-out in a flattened network, with multiple L2 forwarding paths powered by TRILL.

The question I have is just how far across the data center does the L2 domain really need to span? Lets say this is a vmware environment. The latest version of vSphere allows up to 32 hosts per cluster. Furthermore, it is only within that 32-host cluster that a vmotion or DRS or FT action can take place. Theoretically, you can configure the vmware cluster to span the entire server farm, end-to-end. But in reality, how are vmware clusters configured? I would think that the hosts in a cluster are largely configured in adjacent cabinets, not across the entire data center. So, do you REALLY need to span the L2 domain across the entire data center server farm?


vmware clusters and L2 Spanning


In my experience, it will start by a few servers in one or two cabinet and at some point in time, you will have esx host in randomly distributed physical location. The chaos is always a strong force in the datacenter....One day, some manager will comme with the idea of an hot backup datacenter in case of emergency. At what point does exceptions become more dangerous to administer then a L2 domain. Also consider opex....


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