With the upcoming elections
Politics.ie has seen its traffic explode, trippling in 2 weeks from 30k pageviews per day to 100k pageviews per day. Six months ago it was only 15k pageviews per day and when it got to the 30k mark we got ourselves a new dual Xeon to keep up.
So heres some things I've done over the past while to reduce the load on the server to cope with the huge increase in traffic.
Installed
eXtreme styles template caching mod - this precomplies the templates phpBB uses.
Removed the CSS from being included inline in each page to a standalone style file saving 12kb per page.
Caching of pages - the most viewed pages are the latest discussions page, the landing page and the index.php page. So by taking a snapshot of each every few minutes, and serving those out, that cut down on the number of pages to be dynamic ally generated. Very simply I just put a check at the top of the php scripts to see if the url matched e.g. '/latest.php' and served out a copy if it did. Only a few pages are suitable to caching. Nobody has complained so far, so it must be working fine.
Turned on mod_expires in apache and set images & javascript to expire in 1 month, thus they will be cached along the way. The mod_mem_cache isnt suitable because of the dynamic nature of most of the pages on the site.
Logged into Googles webmaster tools and asked Google to slow down their crawling (they were asking for 80k pages per day).
I've also optimized the mysql queries, but thats for another day. All in all the above things reduced the load a fair bit, but the load is continuously rising so the reduced load is used up.