increase in dropped udp datagrams

[Robert Schulze]

Hi,

we are running an NFS server (8.2-STABLE/amd64 from 2011-09-08) with 
several 8.1-RELEASE-p1/amd64 clients (webservers). After updating the 
server, we now realize a slight increase in udp datagrams "dropped due 
to full socket buffers", which wasn't the case in the previously 
installed 8.2-STABLE from 2011-05-08. This also results in higher 
averages in HTTP request time on the clients.

Nothing was changed on the configuration regarding sysctls or loader 
tuneables.

kern.ipc.maxsockbuf is at 1024000 on the server.

Was there a change which could cause the drops? Should this tuneable be 
increased further?

Regarding maxsockbuf: is this number per-socket? So does one have to 
keep in mind that there could be maxsockbuf*maxsockets allocated for UDP?

I'm willing to provide further information upon question.

with kind regards,
Robert Schulze