proxy_cache_path's max_size being violated/ignored

[gwinans]

Hi folks,

We setup some nginx instances a few months ago in order to serve up/cache
video content. Recently, we've noticed that there is *severe* cache overrun
-- on the order of 1TB + per cache directory.

It seems like proxy_cache_path is entirely ignoring the max_size value
specified in the config.

Here's the config as it stands:

http://pastie.org/private/aoc4nwyrdagtiwrmgmtjma

The actual cache size on-disk is ~1.1-1.4TB rather than the expected 320GB.
I'm at a loss after having asked for days on end in the #nginx channel on
freenode.

Did I pooch the config? Is the nginx cache loader unable to keep up with the
incoming data rate? Is the max_size value arbitrarily ignored for some
reason?

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