> What I'd love to see is the avg spec and numbers of machines in each > section. So how many proxy, mod_perl and search servers were required to > give the phenomenal performance you managed to achieve.
Well, this was a long time ago (I wrote the article over a year ago), and I don't remember exactly. The proxy machines were pretty basic, the search servers were heavy on CPU power, and the mod_perl servers were heavy on RAM. There were a lot of machines in the cluster, but I don't remember exactly how many and it changed over time. There were dozens of mod_perl servers when the cluster was at its biggest. Most of them were idle for the majority of the time, but they were all needed for the occasional peak load. I remember at one point I was feeling embarrassed about the number of machines and I told one of our sysadmins that it might have been a better strategy to get a big Sun box or two instead. He replied that a Sun box with equivalent power would have cost about 10 times as much as what we paid for our rackmounted Intel machines. After that, I didn't worry about it too much. - Perrin
