- Plesk 12.5 for Linux
- Plesk 11.x for Linux
- Plesk 12.0 for Linux
The site active users being dropped and the site page became unavailable.
In the domains
file the following entries can be observed:
2014/12/12 13:41:38 [error] 4459#0: *881104 connect() to unix:/var/www/vhosts/system/domain.com/php-fpm.sock failed (11: Resource temporarily unavailable) while connecting to upstream, client: 18.104.22.168, server: domain.com, request: "GET /in/?u=cm9ja2VuaW5uYW5hbm5lfGlufDI1MHwxfDN8fG5vfDV8dW5kZWZpbmVk HTTP/1.1", upstream: "fastcgi://unix:/var/www/vhosts/system/domain.com/php-fpm.sock:", host: "domain.com"
This is software issue #PPPM-2357
By default, interaction between NGINX and PHP-FPM is configured to use UNIX sockets. Sites with high load are exceeding OS limitations. However, there are no options in Plesk GUI to change from UNIX socket to TCP at the moment. And manual changes in configuration files for domains are getting overwritten by Plesk.
The issue will be fixed in future versions of Plesk.