即使没有达到限制，php也会产生新的子级。

Question

我的php过程给我以下警告：

[29-Apr-2014 13:06:10] WARNING: [pool www] seems busy (you may need to
increase pm.start_servers, or pm.min/max_spare_servers), spawning 8
children, there are 19 idle, and 51 total children

[29-Apr-2014 13:07:09] WARNING: [pool www] seems busy (you may need to increase
pm.start_servers, or pm.min/max_spare_servers), spawning 8 children,
there are 14 idle, and 47 total children [29-Apr-2014 13:07:10]

WARNING: [pool www] seems busy (you may need to increase
pm.start_servers, or pm.min/max_spare_servers), spawning 16 children,
there are 17 idle, and 53 total children [29-Apr-2014 13:07:11]

WARNING: [pool www] seems busy (you may need to increase
pm.start_servers, or pm.min/max_spare_servers), spawning 32 children,
there are 14 idle, and 56 total children [29-Apr-2014 13:07:12]

WARNING: [pool www] seems busy (you may need to increase
pm.start_servers, or pm.min/max_spare_servers), spawning 32 children,
there are 19 idle, and 62 total children [29-Apr-2014 13:07:13]

WARNING: [pool www] seems busy (you may need to increase
pm.start_servers, or pm.min/max_spare_servers), spawning 32 children,
there are 18 idle, and 63 total children [29-Apr-2014 13:07:14]

我的fpm.conf是：

pm.max_children = 161
pm.start_servers = 20
pm.min_spare_servers = 20
pm.max_spare_servers = 40
pm.max_requests = 1000

我的问题是

1. 为什么即使我没有达到max_children值，也会产生子级？是否因为交通挤迫，而游手好闲的儿童最少要达到20岁，才能用完呢？
2. 这在我的系统上造成了开销吗？

Answer 1

为什么即使我没有达到max_children值，也会产生子级？

因为那是最大的。一旦达到最大值，就不会再创建更多的内容，但在此之前，PHP将在需要额外容量时添加工作人员。使用您的设置，您将始终拥有至少20台服务器，不超过161台，FPM将在不足20台空闲时添加服务器，在超过40台空闲时删除服务器。

Answer 2

您有pm.min_spare_servers = 20，它将在20个空闲的儿童限制和产卵更多，以恢复到min_spare_servers的数量。降低这个值以减少它发生的频率。这是为了抵消负荷尖峰和有足够的孩子，以满足需求。