How to recover RAID 10 from Mobius 5 Bay RAID array?

Question

I have a Mobius 5 Bay RAID array, with 10TB in each drive. I have it set to RAID 10.

Recently I switched off and on my house's power breaker with this device on it, and now when it starts it fails with beeping and a purple error light on drive 2 (and sometimes 1-3..?).

I've tried popping the drive out and back in, but that doesn't work. Is there a way to recover my data short of buying another $200 drive?

I believe drive 2 should be mirroring drive 1. Can I somehow validate that the error is a hardware one and that drive 2 can't just be rebuilt from the drive it is mirroring?

The user manual for the Mobius 5 Bay RAID array states:

RAID 0 (Striping) is a non-redundant data mapping technique. It combines data evenly across multiple drives simultaneously, increasing performance.

• In Striping mode, it will be viewed as one single storage unit. If one disk in the RAID System fails, all data in installed disks will be lost.
• The total capacity = smallest drive x the total number of drives. For example, if the smallest drive is 1TB, the capacity will be 5 TB when 5 drives are installed.

…

RAID 1 (Mirroring) consists of two drives storing duplicate copies of the same data. In this mode, the data is simultaneously written to two disks. The speed of operation is slow in comparison to other RAID modes.

• Only 2 HDDs (bay 1 and 2) are allowed for the function to perform properly.

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RAID 10 combines RAID 0 and RAID 1 in one single system. It creates two sets of striped disks and then mirrors these sets.

• Only 4 HDDs are allowed for the function to perform. If 5 HDDs are inserted, the 5th drive will be used as a hotspare, meaning when a drive fails, the 5th drive will automatically be rebuilt to replace the failed drive.

Again, mine is set to RAID 10 with 5 disks inserted.

I'm having trouble understanding the above, and if it means my disk 2 can be recovered without being replaced.

I bought this RAID array with redundancy in mind, but it doesn't seem very redundant at the moment... Maybe I chose the wrong RAID setting.

Answer 1

With a RAID 10, it should still function fine, though degraded, with 1 drive failed. And depending on the failed drives, it may function normally with 2 drives failed. So you either have 2+ drives failed, or something else is at work.

If you have too many drives failed, buying another drive won't help you get your data. You would need data recovery help. Both drives in a striped 2-drive set (RAID 0) are required to function. You can look up diagrams of how data is arranged with RAID 0, RAID 1, and RAID 10 to understand which situations lead to loss of data.

It's certainly possible to have some kind of failure in the enclosure itself, particularly with power problems. That's a single point of failure as opposed to the drives in the RAID. That may require a new enclosure.

You note that the purple error light shows on drive 2, and sometimes drives 1-3. Is this light just an error light? Or can it show if the drive is in use also? Could it be that drive 2 is failed, but other drives show activity because they are rebuilding to the extra hotspare disk? If it's 10TB, it may need a very long time to rebuild. But the manual does state the data should still be accessible during rebuild. So let's hope the problem is the enclosure (meaning you don't have permanent data loss).

Note that just removing one drive and connecting it by a USB dock to a computer won't achieve much because you'll need a minimum of a certain 2 striped disks for the data to be coherent.

Have you talked to the device company's support? They would probably best know how to diagnose. Just don't let them erase your drives, initialize, format, etc. Some support staff out there don't know what they are doing.

I have to say I recommend making a clone of each of the drives before attempting something that may cause a loss of data. It requires more drives of course. But that way you don't go beyond a point of no return if there is any misstep. Data recovery professionals always do this at the first opportunity.

Answer 2

I contacted the manufacturer and they sent me a new enclosure. I swapped in the drives and they started working again. All drives blue and I can see the device in windows explorer again.

So, it appears to have been an enclosure issue.