Error when trying to start mongodb in the background

vagrant@precise32:~/app$ sudo mongod --fork --logpath /var/log/mongodb.log --db
path ./data
Mon Oct 27 17:50:21.964
Mon Oct 27 17:50:21.966 warning: 32-bit servers don't have journaling enabled by
 default. Please use --journal if you want durability.
Mon Oct 27 17:50:21.967
about to fork child process, waiting until server is ready for connections.
forked process: 5360
all output going to: /var/log/mongodb.log
log file [/var/log/mongodb.log] exists; copied to temporary file [/var/log/mongo
db.log.2014-10-27T17-50-22]
ERROR: child process failed, exited with error number 100