How stable is APC 3.1.x?

Question

Is anyone using APC 3.1.x in production on a high volume site? The 3.1 series is labeled a "beta" release, but it has some features that we'd really like to have (specifically, performance improvements for apc_clear_cache('user') which didn't make 3.0.19)

So: are you successfully using APC 3.1.x on a very active site? (more than 1 PHP request per second [not including images/js/css]) Any signs of instability at all?

Answer 1

I have it running on a production website. For several days - no crushes. I am using Apache worker + php-fpm.

File Cache Information

Cached Files    0 ( 0.0 Bytes)
Hits    4456420
Misses  11090047
Request Rate (hits, misses) 47.89 cache requests/second
Hit Rate    13.73 cache requests/second
Miss Rate   34.16 cache requests/second
Insert Rate 18.27 cache requests/second
Cache full count    4671279

User Cache Information

Cached Variables    64 ( 1.3 MBytes)
Hits    10480405
Misses  298883
Request Rate (hits, misses) 33.21 cache requests/second
Hit Rate    32.29 cache requests/second
Miss Rate   0.92 cache requests/second
Insert Rate 0.74 cache requests/second
Cache full count    34

Now I have been resetup cache size because of high query miss count.

Answer 2

Having been emboldened by FractalizeR's report of success, our ops guy rolled APC 3.1.3p1 to our 4 production PHP boxes (PHP 5.2.5, 5.2.10, 5.2.11) which are seeing 1000-2500 APC "system cache" hits per second currently.

So far so good. I'll report back if anything comes up.