Many interesting posts here. Thanks for sharing. To me, it's the total "stack" that counts, since everything from the OS to the database to the net setup (such as DDOS protection and handling), to the actual Perl code that runs behind your web pages all comes together in an
implementation that defines how well a web app does or doesn't perform in the real world.
These kinds of post in this thread, sharing real world experiences and implementation details of the "stack" components (OS, database, etc.) people find work well, make us all better Perl Monks, IMO.
Right now, I'm reading up on DDOS defenses. Interesting stuff (feel free to offer suggestions and links).