Kiwi,
I run WordPress sites. I moved over to KnowHost over a year ago, and love it.
This is what I would do....
- Change PHP handler to DSO
- Add mod_ruid2 (for security reasons with DSO)
- Install APC opcode cache. Set cache size (apc.shm_size) to 512M for starters (if you are on SSD-VPS3)
- Monitor APC cache fragmentation and usage and adjust cache size as needed (monitor it over several days for an accurate assessment)
- Install the nginxCP cPanel plugin - this runs nginx as a front end reverse proxy (MUCH better performance on HTTP requests than Apache)
- Upgrade to PHP 5.4 (latest release), as it shows better performance for WordPress sites than 5.3 version (about 9% better performance, on average)
- Upgrade to mySQL version 5.5 (slightly better performance than
- Install W3 Total Cache plugin
- Set Page Cache = Disk Enhanced; Database Cache = APC; Object Cache = APC;
- Sign up for MaxCDN as a origin pull CDN
- Configure MaxCDN and activate it in W3 Total Cache
- Monitor your servers CPU and memory usage over time. Look for the cause of spikes in usage at various times.
- Install and run the P3 (Plugin Performance Profiler) plugin (it points you in the right direction) and analyze your plugin resource usage. Some plugins are just flat resource hogs, and are very inefficient. Make changes where appropriate.
- Install and run the Query Monitor plugin. Take a look at database queries (too many is obviously a bad thing), and any PHP errors or warnings that may exist. Make changes where appropriate.
- Treat the KnownHost people with respect, as they really do have your best interests in mind
The above server configuration works VERY well for my WordPress sites . KnownHost Support was
VERY helpful and patient while working with me on getting my VPS configured. Honestly, they are the best hosting support group that I've come across (I've tried 4 different hosts prior to KH).
If you have not made attempts to optimize your WordPress install, and taken some or all of the steps above to optimize your server configuration, then increasing your server resources will not help you. You need to get to the root cause, and solve it.
I hope this helps you.