You need to have database backups to recover from database failures. The backups are created with database tools. The exact backup procedure depends on your database product and likely on the configuration of your database. The chronological order of the backups is crucial:

Caution

Note, that recovery will work correctly, if this given chronological order of backups is respected. The content of the Content Management Server must be newer than the content of the collaborative component's database. The time between the single backups should be short.

See Content Server Manual for information how to back up the Content Server's database.

You can find an overview about backup of MongoDB and possible backup strategies here.