[semprot]

Originally Posted by NiteWave

did some search, have not found a simple way to disable user variable cache.

for fragment, it's more relating to add/delete cache entry frequently.
since you set
apc.ttl 0
apc.user_ttl 7200
which add operation can be 0 if shared memory always have free space(in your case). but if php script use apc_delete() to delete cache entry purposely, it will cause fragment.

My site has guests & logged in visitors. For guests, the view is cached entirely by APC (i think) to speedup site. Considering the amount of guests and cached pages, i agree maybe add operation is frequent. But apc_delete is not used frequently on my site i believe, because i set the script to cache on long time (5 hours).