UC on UCS

Wanted to make sure everyone was aware to make this change on all Virtualized Unified communications.  This is a known issue with VMware and Linux host.  I have seen this cause very weird issues on a UC deployment.  

http://docwiki.cisco.com/wiki/Disable_LRO

Note:

After upgrading the ESXi host to 4.1 or 5.0 and upgrading VMs to VMwareTools to 4.1 or 5.0, you may experience slow TCP performance on VMs running on the 4.1 or 5.0 ESXi host. You can address this situation by disabling Large Receive Offload (LRO) on the ESXi host.

To disable LRO, follow this procedure:

1. Log into the ESXi host or its vCenter with vSphere Client.
2. Select the host > Configuration > Software:Advanced Settings.
3. Select Net and scroll down slightly more than half way.
4. Set the following parameters from 1 to 0:
   • Net.VmxnetSwLROSL
   • Net.Vmxnet3SwLRO
   • Net.Vmxnet3HwLRO
   • Net.Vmxnet2SwLRO
   • Net.Vmxnet2HwLRO
5. Reboot the ESXi host to activate these changes.
   

Your guest VMs should now have normal TCP networking performance.