Suddenly slow load times
Suddenly some of the internal pages on our website are VERY slow to load (30 seconds). We have made no recent changes to the site. Our web developer says it's not the site, suggests it's the server. Linode says all looks good. What else could it be?
Even without making changes internally to the site, it's possible that some of your resources are being used up which might be causing your site to slow down.
I'd recommend checking on your available memory, inodes and disk space to see if you're running out of resources.
free -m df -h df -i
You could also check which processes are using the most CPU and memory on your server with the following:
top -bn 1 -o %CPU | head -n 15 top -bn 1 -o %MEM | head -n 15
Another thing to consider doing would be tuning Apache and/or MySQL:
Our web developer says it's not the site
Once quick test you could use to help benchmark things would be Google's PageSpeed Insights: