There are three types of database backups:

"L0 (Level 0) backup. This is the most common database backup. This is a complete physical and logical backup of the database from which data can be restored.

"L1 (Level 1) backup. The L1 backup is an incremental backup. It contains a backup of all the data that has been changed since the last L0 backup. It takes much less disk space than an L0 backup; however, it cannot be used for full restoration. If the system fails, you must use both the L0 and L1 backup files to restore data.

"L2 (Level 2) backup. The L2 backup is incremental to the L1 backup, so it needs both the L0 and the L1 backups to restore data.

Cisco Unified MeetingPlace Express uses a combination of L0, L1, and L2 backups and uses an Informix command called ontape for the backup mechanism.

The database backup file is physically located on the system disk, which is the same physical device on which the rest of the Cisco Unified MeetingPlace Express system exists. The system disk can contain up to three automatically-created L0 backups: the current L0, plus the previous one or two L0 backups. The L1 and L2 backups are also kept there. All of the older backups are removed from the system disk during the cleanup process.

http://www.cisco.com/en/US/docs/voice_ip_comm/meetingplace_express/2_0/english/administration/guide/cm20mnt.html#wp1041913