Storage time limit, media cycle
Before implementing an automatic data backup, you should consider the overall backup concept. In particular, the storage time limit and the number of required media and media cycles must be determined.
If the data is of a rather homogeneous structure, relatively few different media pools will be needed. For a heterogeneous structure a media pool should be created for each category or operating system to enable flexible and adaptable strategies. All media can be kept in one media pool.
It is necessary to distinguish between and make decisions regarding short term and long term storage of backed up data. Short term storage is a media cycle, i.e., media are reused for backups on a weekly to biweekly rotational basis. The effect of a proper strategy and implementation is a full, uninterrupted history of the data. This will enable the restoration of small, granular changes in the data, if required.
In addition to this cyclical usage of the storage media for daily or weekly backups, you should also store backup snapshots in long term storage. These snapshots would include end of month, end of quarter and/or end of year.
Implementation of a cohesive and understandable backup strategy is critical to the smooth operation of your IT infrastructure.
Ultimately, you have to decide, how the data will be stored. It is always a compromise between the data volume that is possible and the requirement both for legislative data retention and historical data retention to keep the enterprise fully operational. SEP or its resellers can help you in the overall determination of both; data volume and data retention.
Two different possibilities for the backup strategies are:
- Keeping and storing all backups.
- Advantages: All data can be recovered for any time slot.
- Disadvantages: Loss of oversight - too much data on too many tapes (clarity), excessive storage capacity required and therefore higher costs.
- Using a single media.
- Advantage: Restoring is easier.
- Disadvantage: Only the last day's changes are available.