VMware Distributed vSwitches (VDS) - Design, theory, *real* use cases and examples?

Solution 1:

I do know that a lot of new features are no longer supported on standard switches, such as the network rollback in case of misconfiguration, and network health checking. You can now save and restore your dVS separately, which I think was a big problem for people (which is why some would have recommended avoiding dVS entirely.

I guess there are three reasons why you should use dVS as opposed to standard in 5.1 setups:

• Above mentioned network configuration rollback and health checks
• Ease of management. For vMotion etc, you generally need all your networking identical on all hosts. This is a pain and there is a lot of room for errors when using standard switches. This process is much simpler when using dVS. Because of these features you should also have vmk ports on dVS
• It's my opinion that there wont be much more development on standard switches, I think everything is going to move more and more towards dVS. Ie. I don't think features such as LACP will be moved to Standard switches.
• You can use Network IO to control uplink usage if you require it (if your worried about vmotion saturation etc.)

Solution 2:

The two main benefits to distributed switches are

1. More features.
   • LACP as you mentioned
   • Visibility into the network activity on each virtual port (so you can see the unicast/multicast/broadcast counters for a specific VM in the vCenter interface)
   • CDP advertisements from the vDS to the physical network devices
   • Mirroring/SPAN for monitoring or troubleshooting
   • Netflow
   • Private Vlans
   • And they're required for some features like network I/O control and Cisco 1000V switches
2. Easier management and configuration.
   • When adding a new host with an interface serving the port groups in a vDS, you just need to assign the interfaces to the switch and it's good to go with all of the port groups configured. (Host profiles can achieve pretty much the same end, but making changes in a host profile is much more of a pain.)

I've used them quite successfully since 4.1. It's a big improvement over the standard vSwitch, and it's awesome to be able to add a new VM port group to all hosts in a cluster or configure a new host's networking in two clicks, but I've always avoided using them on the hosts' management interfaces; seemed like a bad idea.