php-fpm seems busy提示

查到php-fpm.log有WARNING，如下：

[04-Jan-2021 01:10:14] WARNING: [pool www] seems busy (you may need to increase pm.start_servers, or pm.min/max_spare_servers), spawning 32 children, there are 0 idle, and 309 total children
[04-Jan-2021 01:10:15] WARNING: [pool www] seems busy (you may need to increase pm.start_servers, or pm.min/max_spare_servers), spawning 32 children, there are 0 idle, and 339 total children

 

php-fpm.conf的配置：

[global]
pid = /usr/local/php/var/run/php-fpm.pid
error_log = /usr/local/php/var/log/php-fpm.log
log_level = notice

[www]
listen = /tmp/php-cgi.sock
listen.backlog = -1
listen.allowed_clients = 127.0.0.1
listen.owner = www
listen.group = www
listen.mode = 0666
user = www
group = www
pm = dynamic
pm.max_children = 1024
pm.start_servers = 30
pm.min_spare_servers = 30
pm.max_spare_servers = 1024
request_terminate_timeout = 300
request_slowlog_timeout = 0
slowlog = var/log/slow.log

其中max_spare_servers不是已经大于上面WARNING的值，但是仍然报了502 busy的错.

原因：

net.core.somaxconn的值过小，它定义了系统中每一个端口最大的监听队列长度，这个全局参数默认为128

查看net.core.somaxconn的值:

cat /proc/sys/net/core/somaxconn

修改net.core.somaxconn默认值:

echo 1000 /proc/sys/net/core/somaxconn