service mongod start 以后就报下面的错误.

Starting mongod: Wed May 29 16:32:31.518 
Wed May 29 16:32:31.518 warning: 32-bit servers don't have journaling enabled by default. Please use --journal if you want durability.
Wed May 29 16:32:31.518 
about to fork child process, waiting until server is ready for connections.
forked process: 17684
all output going to: /var/log/mongo/mongod.log
ERROR: child process failed, exited with error number 100
                                                           [失败]

谁知道这是为什么呢?

找到原因了 google半天 发现说是没有正常关闭mongod服务,导致mongod被锁. 删除掉mongod里的mongod.lock 文件. 重新启动服务就行了.