HAProxy, NGINX and Rails anyone?

[Willy Tarreau]

On Thu, Jul 31, 2008 at 03:20:09AM -0400, Brian Gupta wrote:
> That said, I'm surprised that they selected nginx for load
> balancing, as they were only able to push 1.2GB of traffic through
> nginx. Haproxy has been tested all the way to handle a full 10GB of
> traffic through a single server.

Be very careful Brian, I think you're mixing two things. It's probable
that wordpress tested on real-world traffic, while my benchmark was
meant to find the absolute maximum performance. Real-world benchmarks
are used to estimate the ability to do the job properly. Component
benchmarks are used to find the bounds beyond which you're sure you
will never go.

Now, that said, I know about people who have a handful of machines
all saturating gig pipes all the day with moderate CPU usage. And
judging by the workload (large transfers essentially, no problem
with running one process per CPU core), it should be possible to
use a 10 Gig NIC in one single machine. But this case is extreme,
as most people serve smaller files. From my first series of tests,
you need to serve files larger than 50kB in average to go beyond
5 Gbps (that was about 13000 hits/s). And you needed an average of
500kB to reach 9 Gbps.

You should also be aware that reaching these loads on one machine
requires a lot of system tweaking. You can run out of memory in
seconds, and if the system runs low on network buffers, you observe
terrible performance. It's always a trade between raw performance
and reliability.

These days, I would say that 10Gig becomes affordable but a lot
of work is required to get the best of it, while reaching gig
speeds is almost a child's game.

Regards,
Willy