MongDB 啟動警告 ”WARNING: soft rlimits too low.“問題解決一例

MongoDB 3.4啟動的時候有如下告警:
# mongo
MongoDB shell version v3.4.13
connecting to: mongodb://127.0.0.1:27017
MongoDB server version: 3.4.13
Server has startup warnings: 
2018-02-27T15:03:18.518+0800 I STORAGE  [initandlisten] 
2018-02-27T15:03:18.518+0800 I STORAGE  [initandlisten] ** WARNING: Using the XFS filesystem is strongly recommended with the WiredTiger storage engine
2018-02-27T15:03:18.518+0800 I STORAGE  [initandlisten] **          See
2018-02-27T15:03:19.055+0800 I CONTROL  [initandlisten] 
2018-02-27T15:03:19.055+0800 I CONTROL  [initandlisten] ** WARNING: Access control is not enabled for the database.
2018-02-27T15:03:19.055+0800 I CONTROL  [initandlisten] **          Read and write access to data and configuration is unrestricted.
2018-02-27T15:03:19.055+0800 I CONTROL  [initandlisten] ** WARNING: You are running this process as the root user, which is not recommended.
2018-02-27T15:03:19.055+0800 I CONTROL  [initandlisten] 
2018-02-27T15:03:19.055+0800 I CONTROL  [initandlisten] 
2018-02-27T15:03:19.055+0800 I CONTROL  [initandlisten] ** WARNING: soft rlimits too low. rlimits set to 4096 processes, 65536 files. Number of processes should be at least 32768 : 0.5 times number of files.


 檢視系統限制：
#  ulimit -a
core file size          (blocks, -c) 0
data seg size           (kbytes, -d) unlimited
scheduling priority             (-e) 0
file size               (blocks, -f) unlimited
pending signals                 (-i) 192979
max locked memory       (kbytes, -l) 64
max memory size         (kbytes, -m) unlimited
open files                      (-n) 65536
pipe size            (512 bytes, -p) 8
POSIX message queues     (bytes, -q) 819200
real-time priority              (-r) 0
stack size              (kbytes, -s) 10240
cpu time               (seconds, -t) unlimited
max user processes              (-u) 4096
virtual memory          (kbytes, -v) unlimited
file locks                      (-x) unlimited


解決方法:
可以直接在當前shell中設定：ulimit -n <value>
例如:


    ulimit -f unlimited  
    ulimit -t unlimited  
    ulimit -v unlimited  
    ulimit -n 64000  
    ulimit -m unlimited  
    ulimit -u 64000  
永久生效，需要寫入到/etc/profile


改完後需要重啟 mongod服務
>use admin
>db.shutdownServer()