Tuning Nginx as a Load Balancer

[W. Andrew Loe III]

Turning on the SSL cache has been a good win so far.

ssl_session_cache shared:SSL:10m;
ssl_session_timeout 5m; # default, included for completeness

On Tue, Jul 13, 2010 at 10:13 AM, W. Andrew Loe III
<andrew at andrewloe.com> wrote:
> I'm running the 0.7 branch as the front door to 6 machines running
> nginx + passenger. The two workers (two core machine) are using a
> modest amount of CPU but I am still seeing spikes in my queue time
> metric. I've patched my instance to add a X_REQUEST_START header
> similar to this http://gist.github.com/318681
>
> According to my metrics, http://skitch.com/waloeiii/dcj79/queue,
> somewhere around 200-250ms of each request is spent in 'queue time'.
> My site runs 100% under SSL so a large portion of that is the SSL
> negotiation, but I think there is room to improve. These machines are
> all in ec2's cloud with latencies < 1ms and plenty of spare capacity
> so I'm pretty convinced that my load-balancer just needs some
> tweaking. My nginx.conf for the load-balancer is here:
> http://gist.github.com/474180
>
> The load-balancing instance has 1.7GB of RAM, however over 1.5GB is
> free. Can I change some of the settings to allow nginx to keep more
> requests off the disk without opening my self up to possible denial of
> service? iostat/vmstat does show pretty consistent writes to the disk,
> but nothing like maxing it out. The X-REQUEST-START is only tracked on
> GET requests as well so slow client uploads should not be throwing off
> the numbers.
>