Looking for tips, hacks, etc. for using VB in a load balancing environment. Currently we have 14 front end webservers and 4 database servers running the site. Our site gets only about 30k uniques per day, but at high traffic times we can have as many as 30k online at any given time. we have the extra server capacity so we don't go down during these high load times because we generally gain a lot of new registrations and paid subscriptions.
14 frontend? for only 30k uniques? Sounds a bit over the top.. My quad core 4gb box in softlayer handles 45k per day for a busy forum - no issues. afaik, vb is able to be used on load balanced systems - replicate via mysql is a choice.
Have you evaluated where the bottleneck is? Is it the web servers or the database servers. That's quite an elaborate setup so I'm very curious. vbulletin can handle a multi server environment so I don't see that as an is issue. You could probably improve things by using specialized applications for specific portions of the site. So specific servers for serving the images for example. If you're using Apache maybe switching to lighthttpd, ngix or litespeed might increase capacity.