NetApp FAS, AFF & ONTAP Data Recovery

WAFL (Write Anywhere File Layout) is NetApp's proprietary file system. Unlike ext4 or NTFS, WAFL uses a copy-on-write structure with indirect block trees, native snapshots and periodic checkpoints (consistency points or CP). It does not exist on any standard operating system: you cannot mount a WAFL volume on Linux or Windows. Recovery requires tools that understand the WAFL inode structure, block maps, the relationship between snapshots and active data, and the 520-byte per sector format that NetApp uses on its disks.

RAID-DP (Double Parity) is NetApp's equivalent of RAID 6: it tolerates the simultaneous failure of 2 disks in a RAID group. It uses horizontal + diagonal parity. RAID-TEC (Triple Erasure Coding) adds a third parity level and tolerates 3 simultaneous failures. RAID-TEC is mandatory in ONTAP 9.x for RAID groups with high-capacity disks (4TB+). From a recovery perspective, RAID-TEC offers more redundancy for rebuilding missing data, but its structure is more complex to analyse offline.

Yes, in many cases. WAFL maintains snapshots as pointers to immutable blocks. Even when the active file system is corrupt (the «live» data is unreadable), blocks referenced by earlier snapshots may be intact on disk. We can navigate the snapshot chain offline and extract previous versions of files. This is one of the advantages of WAFL's copy-on-write design that we actively leverage during recovery.

Yes. NetApp formats its SAS disks with 520-byte sectors (512 bytes of data + 8 bytes of T10-PI checksum). Most standard recovery tools assume 512-byte sectors and fail when reading NetApp disks. Our equipment supports native 520-byte sector reading, which is essential for correct cloning. Additionally, the extra 8 checksum bytes allow us to verify the integrity of each block read.

Yes. E-Series (EF600, E2800, E5700) use a different storage system from ONTAP: pure block storage with RAID 5/6 or DDP (Dynamic Disk Pool). They do not use WAFL. Recovery involves rebuilding the RAID/DDP offline and then mounting the exported LUNs, which typically contain VMFS (VMware), NTFS or ext4. The DDP format distributes data non-contiguously across all disks in the pool, requiring specific tools for its reconstruction.

A system with 48 SAS disks requires approximately 3-5 days for cloning alone (depending on disk capacity and condition). RAID-DP/TEC reconstruction and WAFL analysis can take an additional 4-12 days. In total, a standard case is resolved in 10-20 business days. For critical emergencies (company without access to production data), we can parallelise the cloning of multiple disks simultaneously to reduce timeframes, at the urgent surcharge of +50%.