The mongod server does not daemonize correctly. When using --fork it only fork's once and sets the session id. It really needs to fork an additional time and also close stdin/stdout/stderr.

This is causing an issue for us when we do our backups of mongodb. Our process is:

1) ssh root@hostname "/etc/init.d/mongod stop"
2) rsync the db directory
3) ssh root@hostname "/etc/iint.d/mongod start"

This can also be replicated without using an init script by running a command like:

ssh root@hostname "/usr/bin/mongod --fork --logpath /var/log/mongo/mongod.log --dbpath /data/mongo/db"

This will should return, but it does not. It hangs. I have verified that this can be fixed by having mongod close stdin/stdout/stderr if you use --fork.

For reference http://www.svbug.com/documentation/comp.unix.programmer-FAQ/faq_2.html#SEC16