A recent discussion in the hallway here lead to a really cool reason to use blades for virtualization. The Dell M1000e blade chassis and the M600 and M605 blades support up to six fabrics - meaning that you can have some combination of Ethernet and fibre channel networks totaling six. This provides enough networks such that the service console, VMotion, and VMs can all have dedicated Ethernet networks - with enough left over for iSCSI or fibre channel storage networks.

The really cool thing is the dramatic reduction in need for Ethernet and/or fibre channel upstream ports. All of the service console traffic can be handled by a single upstream port. If the VMotion traffic is strictly between blade servers, then the upstream ports of this network are not needed. Even if you need to VMotion out of the chassis, the upstream ports needed on your network infrastructure will still be greatly reduced. If you had sixteen standalone servers (like the 2950) then each one would need a port for VMotion, but with the blade chassis you could just up-link what you thought you needed in terms of bandwidth - which would be less than 16 (probably more like 2 or 4).

Additionally M1000e blade chassis can be interconnected via the Cisco Catalyst Blade Switch 3130G or 3130X modules and managed as a single switch via their Virtual Blade Switch technology. So with multiple M1000e chassis' the savings in terms of upstream port costs can really be big.

Todd