So I have been using memcached to cache lots of data that was the result of queries to the database. Everything left at default, and on average I stored < 40MB in memcache. I used memcache.php to monitor that. Then I decided to switch over to APC and cache things locally because I really did not need memcache (to avoid the TCP overhead?). Then things got big, and I started seeing lots of fragmentation issues. I have a server with 16GB of RAM, and there is plenty to go around, so I assigned APC 2GB. After about 6 hours it filled up to 1.1GB. I think it is getting close to caching everything it can possibly cache. That's a huge difference from what memcache was storing (< 40MB). Not to mention the APC graph shows a whole lot of fragmentation and it is continuing to grow. I'm not sure if this is a problem or not?
Here is a screenshot of what APC.php is giving me: http://i.imgur.com/ey86r.png
Some other notes: apc.gc_ttl = 0; apc.stat = 0;