ubuntu - why can't I start the mongodb

Question

this is the error:

(mysite)zjm1126@zjm1126-G41MT-S2:~$ /usr/local/mongodb/bin/mongod 
/usr/local/mongodb/bin/mongod --help for help and startup options
Wed Apr 27 10:02:41 [initandlisten] MongoDB starting : pid=2652 port=27017 dbpath=/data/db/ 32-bit 

** NOTE: when using MongoDB 32 bit, you are limited to about 2 gigabytes of data
**       see http://blog.mongodb.org/post/137788967/32-bit-limitations
**       with --dur, the limit is lower

Wed Apr 27 10:02:41 [initandlisten] db version v1.8.1, pdfile version 4.5
Wed Apr 27 10:02:41 [initandlisten] git version: a429cd4f535b2499cc4130b06ff7c26f41c00f04
Wed Apr 27 10:02:41 [initandlisten] build sys info: Linux bs-linux32.10gen.cc 2.6.21.7-2.fc8xen #1 SMP Fri Feb 15 12:39:36 EST 2008 i686 BOOST_LIB_VERSION=1_37
Wed Apr 27 10:02:41 [initandlisten] exception in initAndListen std::exception: Unable to create / open lock file for lockfilepath: /data/db/mongod.lock errno:13 Permission denied, terminating
Wed Apr 27 10:02:41 dbexit: 
Wed Apr 27 10:02:41 [initandlisten] shutdown: going to close listening sockets...
Wed Apr 27 10:02:41 [initandlisten] shutdown: going to flush diaglog...
Wed Apr 27 10:02:41 [initandlisten] shutdown: going to close sockets...
Wed Apr 27 10:02:41 [initandlisten] shutdown: waiting for fs preallocator...
Wed Apr 27 10:02:41 [initandlisten] shutdown: closing all files...
Wed Apr 27 10:02:41 closeAllFiles() finished
Wed Apr 27 10:02:41 [initandlisten] shutdown: removing fs lock...
Wed Apr 27 10:02:41 [initandlisten] couldn't remove fs lock errno:9 Bad file descriptor
Wed Apr 27 10:02:41 dbexit: really exiting now

Answer 1

The user account that is starting MongoDB needs to have write privileges to the /data/db/ directory ... you can change this like so ...

This command will change the owner of the /data/db/ to the user account being used.

$ sudo chown `id -u` /data/db
$ mongod 

If you still run into problems with MongoDB starting, you need to delete /data/db/mongod.lock and then run repair on your database ...

mongod --repair

More about the repair command here.