Of massive hardware...
Eh, I've lurked long enough, I'll stick my neck out with a question that may or may not be standard faire. I was going to post to 
hardware, but this seemed more appropriate. I apologize if this isn't the appropriate venue, but it seems to fit. But it's very hardware geeky.
I run a.. moderately popular site serving about 800k DB backed pageloads a day. Everything is almost okay, except that I'm pushing the capabilities of my hardware. From 11AM to about 5PM local time everything slows down because, surprise, my web-farm can't handle any more users.
Quick precee: The web end of the site runs on a trio of ~1gHz servers with 1GB of ram, their ceiling, and during the day the RAM gets used while CPU utilization is relatively sane at something like 40%.
The apache config is pretty tense at 175 MaxClients (from the default 150) and ~60 static FastCGI servers with ~10 transient dynamic FastCGIs and a handful of "vanilla" cgis (that do't get called more than a few a minute). With this setup I'm running at basically 100% memory utilization, barely avoiding swapping to disk.
The question is simple: I'm planning my next round of server upgrades for the upcomming months and I'm unsure of how to continue: should I buy another pair of small web servers with 1GB ceilings to augment the existing farm (bringing it to 4-5 machine with 1GB each), or replace the farm with 2-3 more expensive servers serving more concurrent users that have a 4-8GB ceilings? How many max users can an apache server effectively serve until the law of diminishing returns negates additions in power?
It's the classic question of quality vs. quantity. Cost will be pretty similar because I can build small machines for a song, and if I buy a few really beefy machines I can sell the old small ones to bridge the difference.
hardware, but this seemed more appropriate. I apologize if this isn't the appropriate venue, but it seems to fit. But it's very hardware geeky.I run a.. moderately popular site serving about 800k DB backed pageloads a day. Everything is almost okay, except that I'm pushing the capabilities of my hardware. From 11AM to about 5PM local time everything slows down because, surprise, my web-farm can't handle any more users.
Quick precee: The web end of the site runs on a trio of ~1gHz servers with 1GB of ram, their ceiling, and during the day the RAM gets used while CPU utilization is relatively sane at something like 40%.
The apache config is pretty tense at 175 MaxClients (from the default 150) and ~60 static FastCGI servers with ~10 transient dynamic FastCGIs and a handful of "vanilla" cgis (that do't get called more than a few a minute). With this setup I'm running at basically 100% memory utilization, barely avoiding swapping to disk.
The question is simple: I'm planning my next round of server upgrades for the upcomming months and I'm unsure of how to continue: should I buy another pair of small web servers with 1GB ceilings to augment the existing farm (bringing it to 4-5 machine with 1GB each), or replace the farm with 2-3 more expensive servers serving more concurrent users that have a 4-8GB ceilings? How many max users can an apache server effectively serve until the law of diminishing returns negates additions in power?
It's the classic question of quality vs. quantity. Cost will be pretty similar because I can build small machines for a song, and if I buy a few really beefy machines I can sell the old small ones to bridge the difference.
