Hard drive failure - need help with diagnostics please

[karansaraf]

I need some help please with some hard drive issues.


I have been running a Synology DS211 Network Attached Storage unit with 2x 2TB internal Hitachi 3.5inch HDDs (RAID 1 = identical mirrored drives)

Last week it started making some funny noises, and became inaccessible. I suspected HD failure in one or more drives.

I ran Synology diagnostics on the NAS itself without the HDDs and that was all fine - so definitely not a NAS hardware problem.

I then bought a SATA to USB3 cable to hook up the drives to a Windows computer in order to run the Hitachi WinDFT (Drive Fitness Test) which is their HD diagnostic tool.

Now, when I connect the first drive to the computer via SATA to USB3, and plug in the power, it is making a funny noise (therefore the problem lies with this drive). However:
- Whilst the computer recognises a new piece of hardware being connected, it cannot "install new hardware" and fails at this stage
-I can't seem to find it in My Computer/My Devices and WinDFT doesn't scan for it and recognise that it is connected.


The "good" drive when connected spins normally. The computer recognises a new piece of hardware has been connected, and seems to install drivers successfully. Windows recognises that a "mass storage device" is connected (when I look for it in "My Devices"). However:
- It does not appear in My Computer as an extra drive
- When I go to disk management, it shows up (in addition to my C:/ drive (OS) and E:/ drive (data partition) - but it has no drive letter assigned, has no information available (ie. total capacity, capacity filled etc)
- It tells me that in order to use the disk, I need to "initialize" it. But doing so will erase my data (and this is the only disk left with all my data on it!)
- When I then scan for drives using Hitachi's WinDFT - it cannot even detect that the good drive has been connected.

I'm not 100% sure, but I think Synology automatically format their drives in EXT format (I think).


What do I do next? How do I get the drive recognised in Windows?

Many thanks for your help.

 

[davexnet]

Perhaps connect the drive to a Linux box (or boot a "Live" Linux CD)and see if linux
can read it.

 

[Paperdoc]

In any RAID1 system the data written to the Partition Table at the beginning of each member HDD unit is NOT what would normally be written on a stand-alone drive. Hence, Windows cannot understand that apparently good HDD unit and will not try to display for you any of its data.

When one member of a RAID1 array fails and is detected by the RAID controller, normally its default action is to "break" the RAID array back to a pair of separate HDD units, isolate the faulty unit, and let you keep running from the remaining good one. I suspect strongly that what this means in practice is that a little of the Partition Table data is re-written in what Windows would consider a "normal" manner so that Windows CAN use the good unit as a stand-alone drive temporarily. (Many RAID systems also allow you to use a tool to force this "break the RAID array" thing manually if you choose.)

From your post it appears that the Synology system did not detect a failed HDD in the array and do this change. However, because of your suspicions you believe you have found the culprit and know what to replace. Now, in cases of a failed member of the RAID1 that are detected automatically and treated as above, the next step normally is to replace the failed unit with a new good one of suitable size, then tell the RAID system to repair the array. This means it will detect which drive unit is new and empty, copy everything over from the remaining good one, and re-establish the RAID1 array. I STRONGLY recommend you find and read the Synology system manual for RAID1 for exact details on how you should do this. Bear in mind that your situation is a slightly different from the usual. It appears the Synology system did NOT detect a flaw and break the array. However, even if it does not yet believe there is a flaw, it may make that decision quickly if you replace the failed unit with an empty one.