I'm having an issue with memcached. Not sure if it's memcached, php, or tcp sockets but everytime I try a benchmark with 50 or more concurrency to a page with memcached, some of those request failed using apache ab. I get the (99) Cannot assign requested address error.
When I do a concurrency test of 5000 to a regular phpinfo() page. Everything is fine. No failed requests.
It seems like memcached cannot support high concurrency or am I missing something? I'm running memcached with the -c 5000 flag.
Server: (2) Quad Core Xeon 2.5Ghz, 64GB ram, 4TB Raid 10, 64bit OpenSUSE 11.1