My APC always hits 100% Fragmentation. My VPS has 1GB of ram, APC has 256mb allocated to it, but it's only using 100mb on avg(150mb max) out of the 256mb.
I have to restart php-fpm, the 100% Fragmentation slows down my site. Any recommendations?
100% fragmentation don't slow down your site. It is just a problem if APC need to store a big file and there is no place to put it.
Do you use user_cache in your application ?
Do you use apc.php to see how much ram it uses ? The diagram must remain stable. If it change every time then APC is not configured properly.
What kind of website is running on your server ? Some require fine tuning. For example Magento require a max file size of 20M.