I'm running into a rather nasty issue, and hope that anyone here can help me with a possible solution as I'm pretty much brickwalling right now.
- I have an OpenVZ VPS that is configured with VSwap
- My VPS provider has confirmed there is still plenty of host cpu/ram/etc available on the node
- I've done a textbook LEMP install, tried both CentOS 5 and 6.3 with the same results
- php-fpm runs OK with phpinfo(); and gives the proper output, so nginx and php itself seem to be doing just fine
- installing phpMyAdmin to manage the database, I ran into my problem: First time around, it would give a phpMyAdmin error, with the dreaded Bad gateway 502 upon reload. The log file for php-fpm shows a SIGSEGV
- php-fpm won't recover from this, unless I manually restart the service
- Looking at extensions and disabling them one by one, it seems the Segfault is caused by APC, because disabling it removed this. This makes me think it's a memory management issue somewhere with shared memory.
- Further suspicions about the previous point is the fact that a more traditional VPS on OpenVZ with the same provider (using burst/beancounters) with the exact same setup runs fine.
- Disabling APC and other extensions, leaving just the required ones, still doesn't give me the phpMyAdmin, and just gives me an error to check the php configuration and that I should check the logs.
- The logs, however, do not give me any information.
- Nginx logs just tell me: 797#0: *20 recv() failed (104: Connection reset by peer) while reading response header from upstream
- PHP-FPM error logs do not give anything at all (no logging).
Does this mean VSwap is bad? Am I doing something wrong? once again I've done a textbook install using "if not true then false" guides on 2 versions of CentOS, and one VPS runs fine (no VSwap) while the other does not (VSwap), with really no difference otherwise as far as I can tell.
Edit: I've tried different versions and architecture of client O.S. (CentOS 5.* and 6.*, x86 and x64) and different versions of all LEMP components and phpMySQL and it makes no difference. On the plus side, what I needed phpMySQL for can possibly be done with other software and the fora I need a database management tool for running on phpBB3 seem to do just fine. But it's still weird and aberrant behavior.