I'm currently running php5 with APC, the latter with default configuration. However after setting up munin to monitor APC, I'm surprised by the results:

apc.shm_size: 30
apc.gc_ttl: 3600
apc.ttl: 7200
Used: 14MB
Request rate: 100 requests/second
Fragmentation: 0
Hit ratio: 80% (dropping to 0 a few times per hour)

So the obvious question: how can I adapt the configuration to achieve a higher hitrate. I find it very strange that the available memory is not fully used which the hitratio is still below what I would expect.

Here's my munin chart showing the strange hit ratio drops:

It seems that sometimes all pages are removed from the cache, but the amount of purges is zero...


Thank for any hints!