Which mechanisms are used to maintain data integrity in NetApp storage?

• A. WAFL, checksums, and RAID parity
• B. RAID 0 stripping only
• C. Data encryption at rest only
• D. Backup to external device only

Answer: (A)

Maintaining data integrity in NetApp storage hinges on three mechanisms: WAFL, checksums, and RAID parity. WAFL (Write Anywhere File Layout) is NetApp’s file system that uses copy-on-write and metadata journaling to keep the file system in a consistent state even after crashes or power loss. This design helps ensure that writes don’t leave the system in an incomplete or corrupted state and that data can be recovered to a valid point. Checksums are computed for data blocks and metadata and are verified when data is read; if a discrepancy is found, the system can detect corruption and repair it using redundant information. RAID parity distributes data with parity across disks so that if a disk fails, the missing data can be reconstructed accurately, preserving integrity.

The other options don’t provide the same level of protection: RAID 0 offers no parity or redundancy, so there’s no mechanism to recover from disk failure or detect corruption; data encryption at rest protects confidentiality but not the integrity of data on the storage itself; backups to an external device protect against data loss but don’t maintain real-time integrity or provide ongoing protection of the primary storage.