I upgraded a 4 * ESX 2.5.1 to 3.01 on HP Blades evrything went well. the 4 esx belong to the a cluster, DRS and HA are enabled and automatic. NOw I have a problem with VMotion: when a VM move from one esx to another it can't be ping. and it can't be accessed from the network. Please this a big problem for me as this is a production VMs.
Please help it is very urgent.
are you using NIC teaming ? To troubleshoot, try without (only one uplink in the affected vSwitches), or with port-based NIC teaming.
The VM maintains its original MAC (and IP) address, so the originating machine (running ping) doesn't need to adapt to any change. But the switches see that MAC address on a different port (connected to the destination ESX rather than the source ESX), so the switches need to adapt. That's why the ESXes perform the "notify switches" action.
How many virtual network ports are on your vSwitch? If you have too many VM's for the default 24 ports you can lose network connectivity. Also, double check your vlan config on the switch and make sure you don't have the native VLAN on the switch port the same as one of the vlan's that you are trunking.