On Tue, 06 Jan 2004 15:09:01 -0800, Jimmy Wales wrote:
Gabriel Wicke wrote:
|----------- Bind DNS round robin _______|______ (multiple A records)How well does DNS round robin work in practice as compared to a proper load balancer?
I think it's the solution with the least control on how the traffic will be actually distributed. On the other hand the squids might not be the bottleneck anytime soon, and by that time it would propably make sense to install a second, possibly distributed squid layer. It might as well save some time because the work to install Heartbeat would only need to be done once on the Squids. Once a second Squid layer is installed any separate Linux Directors are not needed anymore (and the Squids will need Heartbeat then). Except maybe for balancing the database, but that's propably a different setup altogether.
I've never tried DNS round robin because people say it sucks. But I have no actual knowledge from first hand experience.
Me neither.
I do know that load balancing using the tools that linuxvirtualserver.org talks about works great, and gives a very good and predictable level of control.
I've asked the squid guys about the load balancing setup: If ICP is disabled (Apache doesn't support it) it would do a dumb round-robin without weighting. With ICP enabled (as a dumb echo on port7) it will take the weighting into account (i'm waiting for the answer on how this works out if the ISP roundtrips are all very quick in case of port7). The best solution would be an ICP daemon that delays ICP responses depending on the system load, then the system load would be 100% the same on all Apaches. If the Apaches are all similar in performance this is an academical question anyway. Linux Director also does it as round-robin with static weighting unless feedbackd is installed.
Gabriel Wicke