on version 2.2.2:
db.shutdownServer() does NOT empty mongod.lock.
but on 2.4.3, it does empty the lock file.

The problem I experienced is:
If mongod.lock not clean, "numactl --interleave=all mongod -f xx" failed to start, but "mongod -f xx" works fine.

Thu May 30 13:10:49 [initandlisten] exception in initAndListen: 10310 Unable to lock file: /u10/mongodata/27017/mongod.lock. Is a mongod instance already running?, terminating
Thu May 30 13:10:49 dbexit:

My question is:
Is this a bug and fixed in 2.4.x?
Is there a workaround for this problem?

Thanks
Jack