MongoDB

FAQ: How to "vacuum" or "compact" a database?

Deleted documents are not removed from disk. Use the repairDatabase() command to reclaim this space:

$ mongo mydb
> db.repairDatabase()

Note:

• This is a blocking operation.
• It (temporarily) requires at least as much space as the database itself to run. (See below for how to dump/restore if you need to workaround this.)

HOWTO: Delete (drop) a database?

$ mongo beebo_dev
> db.dropDatabase()

FAQ: How to backup and restore a database?

Backup (mongodb needs to be running):

# creates "backup" directory, backs up all databases managed by MongoDB
$ sudo mongodump -o backup

Restore (mongodb needs to be running):

# restore
$ sudo mongorestore backup

If you are dumping and restoring so you're able to db.repairDatabase() (which temporarily requires twice the size of the database itself) follow these steps:

# backup as above
$ sudo mongodump -o backup

# stop the server
$ sudo stop mongodb

# delete database files

# restart the server
$ sudo start mongodb

# restore as above
$ sudo mongorestore backup

See backups.

FAQ: What's the difference between mongodump and mongoexport?

It seems that the only real difference is output file format; see SERVER-203. (mongorestore reads the mongodump format.)