[Catalyst] Silently failing PageCache with Cache::FastMmap

[apv]

On my dev box, with the test server and with apache/fcgi, PageCache  
is working fine. On my live box (with DreamHost, test and apache/ 
fcgi), it's reporting that it's caching
   [debug] Caching page / for 300 seconds
but it reports it for every request instead of serving out of the  
cache for X seconds after the first request.

I've looked through the debug output and the POD for all the related  
files. Can't figure it out or find any related info in mailing list  
archive. I updated all my related Cache modules and I believe  
everything that's running is current.

The app is loading these
                 Cache::FastMmap
                 PageCache
last, after session and such.

And the config has
   page_cache:
     set_http_headers: 1
     debug: 1

Any ideas where to poke it to figure out why it's failing and how it  
can fail silently? Surely it has to do with the filesystem or  
permissions underneath? But that causes fatals on my dev box so I am  
not sure where to look…

Also, after I already wrote the above I tried Cache::FileCache  
instead of Cache::FastMmap and it works dev and live. I'm still  
curious why the other won't and which anyone recommends if you have a  
reason for a preference.


–Ashley
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