First of all, I am in no way a professional running a server for about two years from home, so keep in mind that the cause to my problems can be very basic and with a simple solution.
My problem is this: My Ubuntu/Apache2 server is hosting several sites and they work, throw no errors, but are occasionally very slow. The prime example of this is a Wordpress site, where both on the site itself and in the administration, sometimes you click a category and get a normally fast reponse and sometimes you click somewhere (where you've been 5 minutes ago) and the load takes 3-15 seconds. The server used to be fast all the time and now it isn't.
The server is not under any heavy kind of load (as far as I know), upload and download speeds are consistently maximum of table values of the connection.
Another issue (possibly related) is a very slow SSH login. This goes away if I disable reverse DNS lookup, but I have no idea if this is relevant.
Would it be helpful if I provided links to specific domains hosted on my server? Are there any logs/configs worth posting? I am glad to post whatever is required. If there is any information I can provide, let me know.
Thank you for any help you might be able to provide.
By rough estimate is seems to have helped a little when I added entries into
/etc/hosts that forward every root domain with a Wordpress site to 127.0.0.1, but
- it didn't SOLVE the problem, only made it possibly a tad smaller
- it would probably be a crude workaround to a real problem elsewhere even if it worked