Hardware and RAID configuration:
A Netgear ReadyNAS device was configured with 3 drives
One drive failed with head damage, the other two had read errors.
- The data patterns and the superblock helped to determine the RAID configuration.
- We ran an analysis and found that the parity data was intact and sufficient to rebuild the missing drive.
- This NAS used the RAID superblock format. The data was formatted in BtrFS,
a new copy on write (CoW) file system for Linux.
- Further analysis showed that the file system was intact. Both the chunk tree and root tree were valid. The root tree pointed to
other sub-volume trees which were in good condition. Most sub-volume trees pointed to the save sets of B-Tree leaf nodes which
indicated that many snapshots had been taken.
- Using the RAID configuration found at the analysis stage, File Scavenger® can reconstruct the 3-drive RAID 5 with one
missing drive. Since BtrFS was supported in File Scavenger version 5, the quick scan mode immediately
detected the BtrFS volume and successfully parsed the file system.
- Over 50 sub-volumes were found because multiple snapshots had been taken.
- The sub-volumes with the most current data must be manually selected.
- Three sub-volumes with the most current data were restored successfully with less than 1% corruption, mostly due to
bad sectors in the two remaining drives.
- Folder structures were completely reconstructed.