报错信息：
about to fork child process, waiting until server is ready for connections.
forked process: 22200
ERROR: child process failed, exited with error number 1
To see additional information in this output, start without the "--fork" option
解决办法：
1、删除dbpath路径下*.lock文件（dbPath在mongod.conf中）
2、修复 /usr/local/bin/mongod --repair --dbpath=/usr/local/mongodb/data
3、再次启动 mongod -f /etc/mongod.conf