proxy_cache_path's max_size being violated/ignored

[gwinans]

So, I've run without this third party cache purge module since I mentioned a
custom build.

The server is still chewing through disk space and IO remains pegged to the
wall (mix of the cache loader and new cache items). The cache loader seems
unable to keep up -- I've never seen it actually delete anything. Through
watching strace, it's just loading items. Does it not work on the queue
until all items are loaded?

Is there anything I can do to try to alleviate this problem?

Posted at Nginx Forum: http://forum.nginx.org/read.php?2,238200,238244#msg-238244