I am working an issue with UDP drops in a high EPS rate environment (several thousand steady) and struggling with making any changes in the loss rate. (according to netstat -su | grep error).

  This is happening on two nodes, (one running an older syslog-ng 3.2 OSE, the other running a splunk forwarder) but I don't actually think it is making it out of the kernel to either application.

  On the syslog-ng side syslog-ng-ctl stats shows *no* drops at all.

  Increasing net.core.rmem_max and so_rcvbuf together all the way to 64 MB did not seem to make any significant difference.

  This is a RHEL 6 box with 16 GB and 4 cores (virtual - running in an ESX environment)

  Are there other parameters, things I should be looking at?

Thanks,

Jim