I’m a guy who will throw in more hardware to keep up with server load and traffic demand, but from time to time, being able to squeeze every little bit of performance worth the hassle of mingling into applications and server configuration.

WordPress is quite MySQL resources intensive when you are not using file-based cache like WP-CACHE. I agree with what Matt Mullenweg said, WordPress was made to be dynamic – using WP-CACHE beats that purpose. So how do we stand against Digg and SlashDot incoming traffic? Configure and optimize your server (or throw in more hardware if you could), but mostly, a decent server with good optimization should be capable of handling those traffic.

One way to speed things up and reduce queries is using opcode cacher like XCache, APC, or eAccelerator. I personally used APC and was able to handle dig traffic without any problem (server load stays on average of 1.1 on Quad-Core E5430/8GB RAM/MySQL Query-cache enabled); I did not even need to use WP-CACHE when the 47124 unique visitor hits SlashGear.com within that hour we were on Digg’s frontpage.

However, we hit a problem when we did Livecast of Apple’s event. We received over 389716 unique visitors within an hour and APC segfaults on us during the livecast. We did managed to stay online and finished up the livecast but server was painfully slow (I was unable to even stay on SSH – end up using KVM to access our machine / server load was 9.11). So I look for another solution and found XCache. I gave it a shot and wait for another Livecast event. While the next livecast did not receive our record-breaking number of close to 400k, we did get 291912 unique visitors within the one-hour of livecast. Server load topped at 2.42 and everything was flawless.

I’ve since stay with XCache and have not seen any problem with it yet. So if you are running WordPress blog, try add opcode cache into your server to save some server resources (if you have shared host, ask them if they would install it on their machine), and of course don’t forget to enable mysql query cache and optimize your apache configuration.

Reference:

Installing and configuring APC
Installing and configuring XCache
Installing and Configuring eAccellerator