Data recovery of NASdeluxe NDL-21200R RAID 6 server with twelve hard disks

The recovery of the video and audio projects was handled in our Business Service – The job was done after five working days.

4. 1 2018 - Sebastian Evers

Initial data loss situation:

Storage media with data loss:

• NASdeluxe NDL-21200 Server (RAID 6)
  
• Twelve hard disks (Hitachi HUA72303ALA640 and HGST HUS724030ALE640)
• Linux / EXT4
• iSCSI volumes
  

Data specified for recovery:

• Video files (video cuts, project files)
  
• Audio files
• Documents

The embedded production system of a big client suddenly froze, after it was still working correctly on the day before. The controller claimed that all eleven hard disks as well as the Hot-Spare were “healthy” but all project files were corrupt.

The server was carefully shut down. After a reboot the server did not come online, even after several hours. The manufacturer support stated the assumption that the file system might be corrupt.

Analysis and conduction of the data rescue:

The physical examination of every individual hard disk showed no grave damages. From nearly all hard disks 1:1 sector copies were made for the further execution of the analysis. With our special procedures the Attingo technicians were able to virtually simulate the RAID 6 and the destroyed EXT4 file system could be recovered.

Peculiarity:

Since the IT infrastructure of the customer was - except for the servers - Apple based (MacBook, Mac Pro, iMac), all data of the native EXT4 file system needed to be converted into HFS+ file system.

Because of the technical limited conversion process and the enormous amount of data, the recovered data was split up onto several storage media based on the priority of certain project files which were gradually delivered to the customer.