Hi - Many thanks for that.
We're using a full MSSQL copy, not express (I'm a linux sysadmin, so please excuse poor MS terminology).
I'd totally forgotten about vSphere 5 having a linux vCenter option - I would *much* prefer that. Do you reckon it would be happy with 200+ VMs and 4 hosts?
The other dumbo question is: if I "remove" an ESXi 4.1 host from vCenter 4.1 - and later add it to vCenter 5.x, is there any risk that it's distributed vSwitches will get confused or otherwise broken?
Cheers! Tim