Packet discards at VMXNET3 adapter on ESXi host
Strange Packet discards
In the last time I encountered to a strange problem.
The following components have been involved:
Win2008 R2 servers with VMXNET3 Adapters.
Used VMware configuration
- vCenter Server 5.1.0a
- ESXi 5.1 Patch 1
Looking at “netstat -e” shows the following strange output.
The discard counters for for send and receive side were growing and had also the same amount.
The output got my special attention, because the RX and TX counters shows always the same value.
Example “netsat -e” output collected with the tool CRWinNetDiag:
======================= netstat -e =========================== Interface Statistics received send Bytes 1445355112 3181346202 Unicastpakets 1704730 2459144 Non-Unicastpakets 260454 1471 Discarded 657 657 Error 0 0 Unknown Protocol 0 _____________________________________________________________
So the follwing investigation at the ESXi host shows a misconfigured Parameter.
ethernet0.emuRxMode = “0”
The parameter should be enabled in environments with a high multicast rate.
After the parameter was set to:
ethernet0.emuRxMode = “1”
The “netstat -e” output looks like:
======================= netstat -e =========================== Interface Statistics received send Bytes 1345356213 3191356110 Unicastpakets 1804730 2559144 Non-Unicastpakets 250453 1672 Discarded 0 0 Error 0 0 Unknown Protocol 0 _____________________________________________________________
So this problem that in burst situations packets has been discarded could be fixed.
Have you seen this behaviour, too? Please tell me!