NGINX using 100% of the server CPU when testing with Blitz.io

[julianfernandes]

I'm facing an issue here and after six days of looking around I decided to
ask for some help here, after all a million heads can think a lot better
than one.

I have a Ubuntu 14.04 server setup with NGINX, HHVM, PHP5-FPM (as a backup),
Percona MySQL, Memcached (which will be replaced by Redis). I have
fastcgi_cache setup for WordPress and object caching done over memcached.
All cool and dandy in theory, but not in practice.

This is a RamNode OpenVZ SSD VPS with 2GB of RAM and an Intel Xeon E5 with
two cores for my VPS. I also tested on a KVM SSD VPS with 2GB of RAM and an
Intel Xeon E3 with four cores for my VPS.

Running Blitz.io on it the server is getting absolutely murdered by the
NGINX worker processes, which each one using 100% CPU according to top and
htop. I usually run with the following pattern:

    --pattern 999-1000:60 https://www.geeksune.com/blog/hello-world/

That makes makes CPU go to the roof and according to Blitz.io this is the
result of that:

> 135 HITS WITH 57,734 ERRORS & 234 TIMEOUTS

Obviously that isn't good. RAM usage stay under 250MB all the time and it
seems that all those requests from Blitz.io are hitting the cache, as seen
here:

> 54.232.204.19 - HIT [23/Nov/2014:19:06:32 -0200] "GET / HTTP/1.1" 200 7632
"-" "blitz.io; 20bed746e60d4e53401c0c04d245c4eb at 189.101.124.196"

Notice the HIT at the start. I set a new log format and added
$upstream_cache_status to it.

A similar setup on the same machine works just fine with Blitz.io, so there
is definitely something wrong with my NGINX setup and it seems related to
fastcgi_cache. I have the same results every time, even with just PHP5-FPM
with Zend.

Does anyone have a clue about what is happening? My configuration files look
like this:

 - /etc/nginx/nginx.conf - http://paste.ubuntu.com/9236266/
 - /etc/nginx/sites-available/geeksune.com -
http://paste.ubuntu.com/9236282/
 - /etc/nginx/conf.d/includes/ssl.inc - http://paste.ubuntu.com/9236298/
 - /etc/nginx/conf.d/includes/security.inc -
http://paste.ubuntu.com/9236321/
 - /etc/nginx/conf.d/includes/caching.inc -
http://paste.ubuntu.com/9236353/
 - /etc/nginx/conf.d/includes/locations.inc -
http://paste.ubuntu.com/9236366/

Thanks in advance.

:)

Posted at Nginx Forum: http://forum.nginx.org/read.php?2,255158,255158#msg-255158