WARNING: [pool www] server reached pm. max_ children setting (5), consider raising it

Server environment nginx+php5.7+mysql5.5

The program is inexplicable 502 see nginx The log found an error ：connect() failed (111: Connection refused) while connecting to upstream

nginx Run Hengchang , restart nginx The error is still unresolved ,

Find the reason for this error on the Internet , In general upstream All are PHP Caused by the ,

see php-fpm.log Find a warning ：

WARNING: [pool www] server reached pm.max_children setting (5), consider raising it

intend php-fpm Concurrent processes are full , modify php-fpm.conf Configuration information

pm.max_children = 30 // Maximum child process （ The default is 5 individual ）

pm.start_servers = 10   //php-fpm Number of start processes
pm.min_spare_servers = 10   //php-fpm The minimum number of idle processes
pm.max_spare_servers = 24   //php-fpm Maximum number of idle processes for

pm.max_requests = 500   // All child process restart time

And then restart php, Problem solving .