During some network connectivity troubleshooting I discovered that certain Veth interfaces on my VSM are showing regularly occuring OutDiscards.
I was able to diagnose the larger network issues as being related to something else, but now I have returned my attention to trying to determine why certain interfaces are still showing these discards.
It is only happening on select Veth interfaces, and it is very sporadic. One interface gets about 1000 of these per day but they come in bunches of about 100 at a time - so theres roughly 5-10 events happening per day that are causing many drops at once. Other interfaces exhibiting the problem will show anywhere from 10-500 discards per day. About 10 interfaces in total are showing this behavior. The VMs themselves are mostly Windows 2008 R2 but a couple linux virtual appliances are showing small numbers of drops as well.
Reading online I found people give indications that they had these problems with the e1000 type interfaces in VMWare or had driver issues.
All of the most problematic interfaces are in fact VMXNet3 interfaces and I have tried completely uninstalling/reinstalling VMWare tools, deleting and reading the NIC within vCenter, and completely deleting and reinstalling the drivers in Windows without any success at improving the problem.
I did contact TAC at one point but their only suggestion was to get a capture of the traffic as its happening for further analysis. Unfortunately, the 15-30 second window suggested to grab this traffic is just unrealistic. I am not able to sit all day long and run capture after capture on the VEM and hope that I get lucky. Even if I tried I doubt I would be so lucky.
So I was hoping someone on here might have a better suggestion for me of what I could try to alleviate these drops or at least determine what is causing them.
The hardware setup is UCS B230 blades with Palo adapters, Everything on the network is Cisco. Connects up to a 6120 fabric interconnect pair which are vPC'd into our core Nexus 7010 switches. Any other details required to provide assistance please let me know and I'd be happy to provide them.