MongoDB Catch-22 won't let me drop huge collection

Question

So I have a 2TB hard drive with 2 collections in 1 mongoDB.

• Collection 1 is about 500gb and completely essential
• Collection 2 is about 1500gb and needs to be deleted.

I was running a process that accidentally filled up the entire HDD, leaving 0% space. There is literally nothing on the machine apart from a Linux Distro and this mongoDB.

• I would like to delete Collection 2.

In order to do this, I would normally just go into mongo and type db.collection.drop()

However, mongoDB is not currently running. In order to start it, I'm using:

• [bobby@myPC bin]# ./mongod --dbpath /home/mongo &

However, since there is no space on the HDD, it returns:

[bobby@myPC bin]# Thu Feb 14 17:47:10 [initandlisten] MongoDB starting : pid=1264 port=27017 dbpath=/home/mongo 64-bit host=localhost.localdomain
Thu Feb 14 17:47:10 [initandlisten] db version v2.2.3, pdfile version 4.5
Thu Feb 14 17:47:10 [initandlisten] git version: f570771a5d8a3846eb7586eaffcf4c2f4a96bf08
Thu Feb 14 17:47:10 [initandlisten] build info: Linux ip-10-2-29-40 2.6.21.7-2.ec2.v1.2.fc8xen #1 SMP Fri Nov 20 17:48:28 EST 2009 x86_64 BOOST_LIB_VERSION=1_49
Thu Feb 14 17:47:10 [initandlisten] options: { dbpath: "/home/mongo" }
Thu Feb 14 17:47:10 [initandlisten] journal dir=/home/mongo/journal
Thu Feb 14 17:47:10 [initandlisten] recover : no journal files present, no recovery needed
Thu Feb 14 17:47:10 [initandlisten]
Thu Feb 14 17:47:10 [initandlisten] ERROR: Insufficient free space for journal files
Thu Feb 14 17:47:10 [initandlisten] Please make at least 3379MB available in /home/mongo/journal or use --smallfiles
Thu Feb 14 17:47:10 [initandlisten]
Thu Feb 14 17:47:10 [initandlisten] exception in initAndListen: 15926 Insufficient free space for journals, terminating
Thu Feb 14 17:47:10 dbexit:
Thu Feb 14 17:47:10 [initandlisten] shutdown: going to close listening sockets...
Thu Feb 14 17:47:10 [initandlisten] shutdown: going to flush diaglog...
Thu Feb 14 17:47:10 [initandlisten] shutdown: going to close sockets...
Thu Feb 14 17:47:10 [initandlisten] shutdown: waiting for fs preallocator...
Thu Feb 14 17:47:10 [initandlisten] shutdown: lock for final commit...
Thu Feb 14 17:47:10 [initandlisten] shutdown: final commit...
Thu Feb 14 17:47:10 [initandlisten] shutdown: closing all files...
Thu Feb 14 17:47:10 [initandlisten] closeAllFiles() finished
Thu Feb 14 17:47:10 [initandlisten] journalCleanup...
Thu Feb 14 17:47:10 [initandlisten] removeJournalFiles
Thu Feb 14 17:47:10 [initandlisten] shutdown: removing fs lock...
Thu Feb 14 17:47:10 dbexit: really exiting now

I can't remove this collection cause there's no space. And there's no space because I can't remove this collection.

How can I fix this? Is there some way of identifying which mongoDB files in /home/mongo I can take out?

Answer 1

Based on the error message, its complaining about not having enough space for the journal. Its not ideal in a production environment to run with out journaling, but you could try starting with out it while you fix the issue.

./mongod --nojournal --dbpath /home/mongo &

edit: to answer your question though, mongo creates and allocates files per database, not collection. So you wouldn't be able to target a specific file to remove a collection.