Making Applications Scale With Load Balancing (or how the Internet works)

Good paper.

I've been using hybrid hardware/software load balancers since 2004, and over time I came to different conclusions than the author on load balancing algorithms, SSL offload, layer 3/4 vs. layer 7 load balancing, relative performance of SSL on load balancers, etc.

I also place a high value on proxy-capable load balancers for use as a 'control plain' for all ingress into the data centers. I.E. - All Internet accessible content is served by URL filtering, proxy-type, SSL capable load balancers, even if the availability requirements do not warrant redundant web/app servers. This allows us to control access to the application by URL and host header, to filter content as needed, to view and manage the status of all services at a single location, to manage all SSL certs in a single location, to automatically re-direct users to a fail whale when the app is down, etc.

The argument against 'doing it all' with the load balancers generally boils down to performance. My counter to that is my circa 2004 Netscalers have no problems doing 1800 requests/second, all SSL, all proxied, and all content switched/content filtered.

In the PDF it links to http://1wt.eu/articles/2006_lb/ which is the paper in html format. For those that don't want to download the PDF, good read =)

Just a heads up: It's a PDF. (Not that there's anything wrong with that :-)

Good paper. thanks for posting. Rare combination of deep AND highly readable.

I started in the middle and read through before circling and back and seeing it was written by creator of HAProxy. So it was even more impressive how objective/ pragmatic he was about different approaches.