Page 1 of 1

RAID0 Recovery from a WD EX4 NAS

Posted: Sat Jan 02, 2021 7:00 am
by mmarre
Hi there,

I am planning to try to recover data from a WD EX4 NAS.

The situation: I had a disk failure. I shut down the NAS, replaced the broken disk with a spare disk (same model, brand new) and rebooted the NAS. However, the NAS do not trigger a rebuild and was put in status FAILED. The "broken disk" is still readable (I was able to clone it without any error).

I can exclude an error with the SATA ports as swapping the disks within the NAS lead to the same issue on the same hard disk.

So as I am going to connect the disk to a linux PC to investigate the raid using R-Studio my main question for the moment is:
Am I correct that I need to connect the disks as normal SATA disks without using any RAID functionality of the BIOS? Because as per my understanding initializing the disks using the BIOS software raid would destroy the data on the disks.

Best regards
Michael

Re: RAID0 Recovery from a WD EX4 NAS

Posted: Sat Jan 02, 2021 3:53 pm
by Alt
mmarre wrote:
Sat Jan 02, 2021 7:00 am
Am I correct that I need to connect the disks as normal SATA disks without using any RAID functionality of the BIOS? Because as per my understanding initializing the disks using the BIOS software raid would destroy the data on the disks.
You're correct. Just as a normal SATA disk. And better to have an image/clone of the healthy disk, too.

Re: RAID0 Recovery from a WD EX4 NAS

Posted: Sun Jan 03, 2021 1:39 am
by mmarre
Thank you for the feedback.

as far as I understood the documentation there can be created a virtual raid using the raid disk without any write operation to the disks. So I would expect that there is no need for having the clones for investigation. So there should be no risk except that other drives may fail as well. But this is then also true for cloning operations, right?

Re: RAID0 Recovery from a WD EX4 NAS

Posted: Sun Jan 03, 2021 2:37 pm
by Alt
mmarre wrote:
Sun Jan 03, 2021 1:39 am
So there should be no risk except that other drives may fail as well. But this is then also true for cloning operations, right?
Exactly. But you create the image only once. When you recover data you may read the disk many times.

Re: RAID0 Recovery from a WD EX4 NAS

Posted: Sun Jan 03, 2021 2:38 pm
by Alt
Alt wrote:
Sun Jan 03, 2021 2:37 pm
mmarre wrote:
Sun Jan 03, 2021 1:39 am
So there should be no risk except that other drives may fail as well. But this is then also true for cloning operations, right?
Exactly. But you create the image only once. When you recover data you may have to read the disk many times.

Re: RAID0 Recovery from a WD EX4 NAS

Posted: Mon Jan 04, 2021 8:07 am
by mmarre
So I started the process of creating a virtual volume and Autodetect Raid parameters. It's running now for roughly 12 hours on a 16TB Raid 10. Status shows 17.06 MB processed and 60% detection rate. 3 mio offsets found and growing.

The detection rate is not growing anymore since 6 hours.

Any estimation available how long the auto detect for raid parameters will need on a 16 TB raid? I know this is likely hardware specific. I just want to know if this can be normal or if the detection process should already have been completed.

Re: RAID0 Recovery from a WD EX4 NAS

Posted: Mon Jan 04, 2021 9:12 am
by RForce
It shouldn't take more than a few seconds to manually figure out the configuration of a RAID 10. Unless R-Studio recently added it, I'm not sure that you'll be able to recover the newer SQL based file structures used by newer My Cloud devices.