On my web servers I am seeing a high rate (106 over ~13 seconds or 300,000 packets) of zero window update messages sent form my web servers to my database servers during peak traffic.
Firmware is Updated:
I have updated the firmware and driver to the latest versions that dell provides for the BCM5709C cards.
TCP Offload is enabled:
Going off the fact that I see an active "Total Offload TCP Connections" in the Broadcom Advanced Control Suite interface (BACs) TCP offloading is enabled. I also don't see the CPU pegging on the servers.
Window Scaling is enabled:
Window Scaling is enabled but not used much. I see 20 packets with Window Scaling set out of 300,000 packets.
Average round trip time is ~2MS with a max of ~3 MS. CPU usage on the Web servers is not peaking at all.
- I don't believe that the buffers should be filling this much on the web servers .
- Are the other metrics beside CPU I should be looking at to see why the buffers are filling up?
- Given that everything is up to date should I be looking into tuning the TCP parameters on my Windows 2008 Server R2 web servers? What adjustments should I be making if this is the case?