1、啟動mongodb出錯

 WARNING: You are running this process as the root user, which is not recommended.

 解決辦法：切換使用者

2、切換使用者之後又出現 

Unable to create/open lock file: /data/db/mongod.lock errno:13 Permission denied Is a mongod instance already running?, terminating

解決辦法：刪除檔案 data/db/mongod.lock （需要切換到root使用者才能刪除，另外需要在root帳號下修改db許可權 chmod 777 db）

3.WARNING: /sys/kernel/mm/transparent_hugepage/enabled is 'always'  

WARNING: /sys/kernel/mm/transparent_hugepage/defrag is 'always' 

解決辦法：在 usr/local/mongodb目錄下先建立conf資料夾，conf資料夾下建立mongodb.conf

  內容為:

#日誌路徑
logpath=../log/mongodb.log
#啟動日誌不追加,太過龐大
logappend=false
#設定mongodb的db路徑
dbpath=/data/db
#後臺駐留(守護)程序服務執行
fork=true

在 usr/local/mongodb目錄下先建立log資料夾

再次啟動mongodb  命令為 ./mongod -f ../conf/mongodb.conf

about to fork child process, waiting until server is ready for connections.
forked process: 3333
child process started successfully, parent exiting

成功

啟動 mongo  

[[email protected] bin]# ./mongo
MongoDB shell version: 3.2.7
connecting to: test
Welcome to the MongoDB shell.