ESXi 5 All VMs (suddenly) VERY sluggish over RDP, no errors though, Urgent!
We have a cluster of 2 ESXi hosts, running with more than enough resources to run the combined ~42 VMs that are in it. We are working in a 2 network environment currently (due to company buyout and end stages of a merger/migration) so in order to access anything dealing with vSphere, we must connect to the network via an RDP connection from one network to another and then from there connect to vCenter. This has worked perfectly without issue for the past 2 years.
We have made no changes to anything on the VMs or Hosts recently but today we suddenly noticed EXTREME sluggishness when connecting via RDP to any of the VMs and once there vCenter times out after trying to connect for 10 minutes or so. (as a point of note, we do have 1 physical machine that is still on this network and I attempted to access resources the same way and get the same issues). I was able to connect to vCenter once earlier today and saw absolutely nothing that stood out - no errors, warnings, and the performance was at its normal levels. I have a lot of conservative event alerts setup and I am not getting any.
I checked the ESXi host logs and there is not much there, only I/O latency changes with the iSCSI connection, but this is normal for this setup. Not major changes and this is constantly going on without an issue.
None of the machines we are able to RDP into (and by the way, when I mean sluggish, I mean it takes 30 minutes to get to the desktop - on all of them! and then when we try to navigate everything is very sluggish and sometimes never completes a specific task) - none of the machines have maxed out CPU or Memory (from within Windows) and none have anything in event viewer.
We do have a major file share that is on one of the VMs and connecting to it over SMB share it is just as fast as it ever has been.
I am at a total loss of where to even begin here and am looking for some suggestions. Without any errors or warnings, it's like it is not happening!