无法在CentOS 7上启动MongoDB 3.2.1

我跟着这个文档上的CentOS 7安装的MongoDB 3.2.1安装完成后，我改变了所有者和组var/lib/mongo和var/log/mongodb/mongod.log到root:root。

当我使用启动mongodb时service mongod start，它仅显示

Starting mongod (via systemctl):  Job for mongod.service failed. See 'systemctl status mongod.service' and 'journalctl -xn' for details.[FAILED]

我已经运行了两个命令以显示详细信息。

systemctl status mongod.service 表演

mongod.service - SYSV: Mongo is a scalable, document-oriented database.
   Loaded: loaded (/etc/rc.d/init.d/mongod)
   Active: failed (Result: exit-code) since Wen 2016-01-27 18:32:46 CST; 14s ago
  Process: 24913 ExecStart=/etc/rc.d/init.d/mongod start (code=exited, status=1/FAILURE)
 Main PID: 23711 (code=exited, status=0/SUCCESS)

1月 27 18:32:45 server1 systemd[1]: Starting SYSV: Mongo is a scalable, document-oriented database....
1月 27 18:32:45 server1 runuser[24920]: pam_unix(runuser:session): session opened for user mongod by (uid=0)
1月 27 18:32:46 server1 mongod[24913]: Starting mongod: [FAILED]
1月 27 18:32:46 server1 systemd[1]: mongod.service: control process exited, code=exited status=1
1月 27 18:32:46 server1 systemd[1]: Failed to start SYSV: Mongo is a scalable, document-oriented database..
1月 27 18:32:46 server1 systemd[1]: Unit mongod.service entered failed state.

journalctl -xn 表演

-- Logs begin at 日 2016-01-24 16:33:05 CST, end at Wen 2016-01-27 18:32:46 CST. --
1月 27 18:32:15 server1 sshd[24879]: pam_succeed_if(sshd:auth): requirement "uid >= 1000" not met by user "root"
1月 27 18:32:17 server1 sshd[24879]: Failed password for root from 182.100.67.59 port 10013 ssh2
1月 27 18:32:45 server1 sudo[24896]: root : TTY=pts/0 ; PWD=/var/log/mongodb ; USER=root ; COMMAND=/sbin/service mongod start
1月 27 18:32:45 server1 systemd[1]: Starting SYSV: Mongo is a scalable, document-oriented database....
-- Subject: Unit mongod.service has begun with start-up
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
-- 
-- Unit mongod.service has begun starting up.
1月 27 18:32:45 server1 runuser[24920]: pam_unix(runuser:session): session opened for user mongod by (uid=0)
1月 27 18:32:46 server1 runuser[24920]: pam_unix(runuser:session): session closed for user mongod
1月 27 18:32:46 server1 mongod[24913]: Starting mongod: [FAILED]
1月 27 18:32:46 server1 systemd[1]: mongod.service: control process exited, code=exited status=1
1月 27 18:32:46 server1 systemd[1]: Failed to start SYSV: Mongo is a scalable, document-oriented database..
-- Subject: Unit mongod.service has failed
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
-- 
-- Unit mongod.service has failed.
-- 
-- The result is failed.
1月 27 18:32:46 server1 systemd[1]: Unit mongod.service entered failed state.

我使用ssh密钥访问服务器，没有密码。