I dealt with a similar issue in 2001. About 6 mid-range Sun servers (like small refrigerators in size), running Netscape Application Server, with the load distr

I dealt with a similar issue in 2001. About 6 mid-range Sun servers (like small refrigerators in size), running Netscape Application Server, with the load distributed using round-robin DNS (A record round-robin). Due to some DNS servers caching the A record longer than intended, it would create uneven distribution of load -- too much on one server and it'd go bad, requests would start taking too long and it'd start throwing 500 errors or just wouldn't respond. Once it stopped accepting connections, other servers would take on its load (the client would retry to the next IP in the round-robin) but then similar thing would happen to the fifth server, and the rest would follow shortly thereafter in a death spiral. Restarting was a bear. We had to "warm up" the application server by hitting some of the web pages so caches would get populated etc., before opening the system to public traffic (which, as I recall, we controlled with IP address aliases) or else it would die again. Finally we put the system behind an F5 load balancer which resulted in a much more even distribution of traffic -- that, coupled with the "warm up" crawl, let to a greatly stabilized system and highest ever (and growing) page views.