Media condition
The condition of the media also influences which media are selected for backup, for example, media in good condition are used for backup before media in fair condition. For more information, see “Calculating media condition” on page 150.
Adding data to media during backup sessions
To maximize space usage of media as well as backup and restore efficiency, you can select how Data Protector treats the space on the medium left over from the previous backup. This is defined with a media usage policy.
Media usage policy
The available media usage policies are listed below:
Appendable | A backup session starts writing data to the space |
| remaining on the last medium used from a |
| previous backup session. Subsequent media |
| needed in this session are written from the |
| beginning of the tape, hence only unprotected or |
| new tapes can be used. Appending media |
| conserves media space but can add complexity |
| to vaulting, because one medium can contain data |
| from several media sets. |
Non Appendable | A backup session starts writing data at the |
| beginning of the first available medium for |
| backup. Each medium contains data from a single |
| session only. This simplifies vaulting. |
Appendable of Incrementals | A backup session appends to a medium only if |
Only | an incremental backup is performed. This allows |
| you to have a complete set of full and incremental |
| backups on the same medium, if there is enough |
| space. |
Distributing objects over media
The following figures show some examples of how objects can be distributed over media:
148 | Media management and devices |