Anyone seen this before? We've just completed a major LAN upgrade and replaced 12 legacy switches with Cisco 2960's. The LAN is performing very well, but any traffic to and from ESXi VM's is very poor for 100Mb clients. Clients with a 1Gbps NIC are superfast, but anyone on 100Mb is dramatically slower.
File copies and applications which are particularly client-heavy are the most noticeable, and the bigger the file the higher the multiplier. For example, a 250Mb file takes around 2 minutes on a 100Mb machine, but only 6 seconds on a 1Gbps machine!
This is only ESXi to client, client to client is very quick, regardless of connection speed. The issue seems to be ESXi being very harsh with 100Mb machines, almost as though some sort of QoS is in place.
I've disabled QoS on both the VM's and the clients, I've ensured that connection speed and duplex match on both switch, client, VM's and hosts. I can switch a good 1Gbps machine to 100Mb and completely break its transfer speeds, and fix it just as quickly by increasing it to 1Gbps again.
Any ideas?