@sbraiden – I recently helped migrate a site off of wpengine because of performance issues and the price wpengine wanted for more horse power under the hood. Their next level of service was going to cost $3200 a month. I suggested linode.com and was also amused by the fact that wpengine runs on top of linode.
The page generation times for wordpress/buddypress/bbpress along with various plugins (gravity forms, buddypress xprofile custom fields type, gravity forms upload rules, gravity forms wysiwyg, gd bbpress toolbox, cloudflare…) was not good. It is still not where we want it either, unfortunately.
The site is quite active, pushing 30,000 members and over 1.3+ million rows in the posts table. On average the page generation times are about 1.5 seconds for logged in users. Adding a new bbpress topic/reply can time out sometimes though. (still on the list to track down and fix)
We utilize Cloudflare out front for a CDN and their threat/spam protection. Their service is free but if you need more page rules to balance out caching the pro service level is $20 a month.
On linode we have a node balancer in front of two 4 core app server nodes. The app server nodes each connect directly to their own 8 core database nodes in a master master setup. This will be changing down the road once the database indexes are trimmed down with some denormalization. The cost for the node balancer, two 4 core and two 8 core nodes is $260 a month but that’s also allowing for some room to grow, capacity wise.
Server software is a combination of nginx, apache (threaded), php-fpm, glusterfs (upload directory only), memcache, zend opcode cache and mariadb. Nginx is the web server in front of apache which serves up static files from the glusterfs file system. Nginx is caching the static content being served up by apache along with full page caching (fastcgi) for anonymous visitors. Cloud flare is also caching the static content and to date we aren’t having any performance issues with IO and glusterfs.
I hope this helps. It can be done but it takes some effort (and money) to do so.
