[Plugin: W3 Total Cache] Heavy APC fragmentation

I’ve been using W3TC without problem on a site for a while now. I recently added APC caching for database and object caches. The site still works OK, but the APC cache quickly gets very fragmented (e.g. typically 100% fragmentation after a day or so), even though there is plenty of free memory (server has ~1Gb free, and I’ve never seen the cache with more than 50% memory used).

I’ve read lots of pieces on APC and tried everything suggested (e.g. set TTL’s to 0, set apc.stat=0, exclude things like timthumb, only one segment and increased segment size) and increased the TTL’s in W3TC to 7200, but none of it seems to make any difference.

APC reports that the only things in the user cache are W3TC objects (4000 or so after the cache has been running for a while) and the system cache has a few hundred files.

Some more detail is on a post I made on Stack Exchange.

I’m confused as to why I should be seeing such heavy fragmentation even though there is plenty of free cache memory. Since W3TC is the main user of APC on this server, I was wondering if there might be some configuration to W3TC that can help to resolve this?

Any pointers would be appreciated.

https://www.ads-software.com/extend/plugins/w3-total-cache/