RAID (Redundant Array of Independent Disks)
RAID is primarily focused on data redundancy and performance, rather than traditional backup strategies. However, backup retention policies can be influenced by how RAID levels protect data.
| RAID Level | Data Redundancy | Performance | Fault Tolerance | Backup Retention Implication | Use Case |
|---|---|---|---|---|---|
| RAID 0 | None | High | None | No inherent backup; need regular external backups. | High-performance applications needing speed (e.g., gaming) |
| RAID 1 | Mirroring | Moderate | 1 disk failure | Provides redundancy; good for short-term retention (mirrored data). | Critical data requiring high availability. |
| RAID 5 | Striping with parity | Moderate to high | 1 disk failure | Data can be rebuilt; requires external backups for long-term retention. | File servers, small to medium-sized applications. |
| RAID 6 | Striping with double parity | Moderate to high | 2 disk failures | More redundancy; can be rebuilt, but external backups are advisable for retention. | Larger file servers, critical applications with higher protection needs. |
| RAID 10 | Mirroring & striping | High | 1 disk per mirror set | Provides redundancy and speed; suitable for performance-sensitive data with decent retention strategy. | Database servers and high-intensity applications. |
| RAID 50 | A combination of RAID 5 and 0 | High | Can tolerate multiple failures | Better performance with redundancy; external backups important for long-term retention. | High-performance database applications. |
| RAID 60 | A combination of RAID 6 and 0 | High | Can tolerate multiple failures | Offers higher data integrity; external backups are recommended. | Large, secure data environments. |
Key Points:
- RAID is not a Backup Solution: RAID levels provide redundancy and improve performance but do not replace backups. Regular external backups are still necessary.
- Backup Retention Policies: Should be developed based on the level of redundancy provided by RAID and the criticality of the data.
- Data Availability vs. Retention: Consider how quickly you need to restore data (availability) versus how long you need to keep historical data (retention).
Always ensure that you have a comprehensive data protection strategy that includes both RAID configurations and regular external backups.