mongodb 启动 WARNING: soft rlimits too low, transparent_hugepage/enabled is 'always'. never

今天启动mongodb的时候，之前一直没注意，今天发现又warning，想整一整。

下面是告警

2019-09-05T12:00:55.271+0800 I  CONTROL  [initandlisten]
2019-09-05T12:00:55.271+0800 I  CONTROL  [initandlisten] ** WARNING: /sys/kernel/mm/transparent_hugepage/enabled is 'always'.
2019-09-05T12:00:55.271+0800 I  CONTROL  [initandlisten] **        We suggest setting it to 'never'
2019-09-05T12:00:55.271+0800 I  CONTROL  [initandlisten]
2019-09-05T12:00:55.271+0800 I  CONTROL  [initandlisten] ** WARNING: /sys/kernel/mm/transparent_hugepage/defrag is 'always'.
2019-09-05T12:00:55.271+0800 I  CONTROL  [initandlisten] **        We suggest setting it to 'never'
2019-09-05T12:00:55.271+0800 I  CONTROL  [initandlisten]
2019-09-05T12:00:55.271+0800 I  CONTROL  [initandlisten] ** WARNING: soft rlimits too low. rlimits set to 15012 processes, 102400 files. Number of processes should be at least 51200 : 0.5 times number of files.

那我们一个个来解决：

transparent_hugepage ，

上面2个问题可以一起解决：

echo never >/sys/kernel/mm/transparent_hugepage/enabled

echo never>/sys/kernel/mm/transparent_hugepage/defrag

soft rlimits too low

这个问题就是我们不能单单把ulimit -n 那个文件句柄数打开，还得同时提升用户可使用线程数

解决办法有几种，这里介绍一个比较快捷，可以及时生效的：

修改 /etc/security/limits.conf 文件，末尾添加：

* soft noproc 65535
* hard noproc 65535

然后 执行一步 ulimit -u 65535

• 第一步是永久生效process
• 第二步是即时当前会话生效process