To DROBO or not to DROBO: a Successful Data Recovery Story

by admin

DROBO storages systems are very powerful and scalable, but recovery from these units is usually very complex.

DROBO is a series of multi-disk devices, which can be either DAS or NAS. Typically, a DROBO has 5 or 8 drive bays, accepts disks in any combination of capacities and produces maximum size single storage out of them, given the desired fault tolerance. This storage is, in turn, either divided into LUNs (virtual physical drives) and presented to the OS as single USB or virtual physical drive.

To combine several physical disks into a single storage, DROBO uses its own technology called BeyondRAID, which is not like any standard RAID level. The BeyondRAID technology uses a combination of RAID1 and RAID5 for single redundancy and 3-way mirror along with RAID6 for double redundancy. DROBO uses different RAID levels for metadata and user data. More than that, even different block sizes can be used on the same DROBO disk pack and LUN. The possibility to recover DROBO data directly depends on whether you have the map of where all the blocks are written or not.

In this case, the customer has plugged all drives from his broken DROBO to a new one but from a different family.

The result was that the disk set was reinitialized and a different map was overwritten. Luckily the new map was (or maps because actually there is more than a copy) written to different locations so the original ones were preserved.

Logical analysis, anyway, could not find any file or structure: the software had detected the new DROBO file system and was trying to reconstruct it. Why look for a different set of data if I have found a good signature of it?

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