Timeout between NGINX and PHP-FPM running Mageno Community

[dgreg]

The site we are running with magento experience a lot of timeout between NGINX and PHP FPM.
The error message in the NGINX error log is "upstream time out (110: Connection timed out) while reading response header from upstream".
The server is not really loaded. The load average is 5 for 12CPUs.

### Preconditions
1. Magento Community 2.1.4
2. PHP-FPM 7.0.14
3. NGINX 1.10.2 release 1.el7
4. CentOS 7

Any good idea is welcome :-)

Thx

[dgreg · Accepted solution]

Hello,

After some long investigations, we found it was too mush I/O on the disk since we activated the cache block.

This only occurs when a lot of customers visit our site.