启动MongoDB时警告WARNING: soft rlimits too low. rlimits set to 65536 processes, 1048575 files. Number of processes should be at least 524288 : 0.5 times number of files.

启动MongoDB

./mongod --dbpath=/usr/local/mongodb/bin/data --logpath=/usr/local/mongodb/mongod.log --logappend --port=27017 --fork

警告如下

Server has startup warnings: 
2021-09-13T17:16:49.948+0800 I CONTROL  [initandlisten] ** WARNING: You are running this process as the root user, which is not recommended.
2021-09-13T17:16:49.948+0800 I CONTROL  [initandlisten] 
2021-09-13T17:16:49.948+0800 I CONTROL  [initandlisten] 
2021-09-13T17:16:49.948+0800 I CONTROL  [initandlisten] ** WARNING: /sys/kernel/mm/transparent_hugepage/enabled is 'always'.
2021-09-13T17:16:49.948+0800 I CONTROL  [initandlisten] **        We suggest setting it to 'never'
2021-09-13T17:16:49.948+0800 I CONTROL  [initandlisten] 
2021-09-13T17:16:49.948+0800 I CONTROL  [initandlisten] ** WARNING: /sys/kernel/mm/transparent_hugepage/defrag is 'always'.
2021-09-13T17:16:49.948+0800 I CONTROL  [initandlisten] **        We suggest setting it to 'never'
2021-09-13T17:16:49.948+0800 I CONTROL  [initandlisten] 
2021-09-13T17:16:49.948+0800 I CONTROL  [initandlisten] ** WARNING: soft rlimits too low. rlimits set to 65536 processes, 1048575 files. Number of processes should be at least 524288 : 0.5 times number of files.

解决办法：

在MongoDB的配置文件 /etc/security/limits.conf 中加入如下内容：

mongod soft nofile 64000
mongod hard nofile 64000
mongod soft nproc 32000
mongod hard nproc 32000

然后重启MongoDB