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Readynas NV+ v2 - RAID sync finished on volume C. The array is still in degraded mode
Hello,
I've been getting increasing warnings from my ReadyNas NV+ v2 recently about disk 4 having increasing uncorrectable errors. I went ahead and purchased a replacement hard drive and replaced t...
Thanks StephenB, I'll give that a shot. What exactly would this accomplish though? I thought once I pulled the bad drive out, wouldn't the NAS begin rebuilding the array and therefore possibly overwrite some data that was on the other 3 drives?
bolan1 wrote:
Thanks StephenB, I'll give that a shot. What exactly would this accomplish though? I thought once I pulled the bad drive out, wouldn't the NAS begin rebuilding the array and therefore possibly overwrite some data that was on the other 3 drives?
There are some cases where the array is completely rebuilt - for instance, when you insert a third disk, and the RAID is converted from RAID-1 to RAID-5.
But your situation isn't one of those. Your resync was trying to reconstruct the contents of the failed disk from the remaining three. That process doesn't change the other three drives. It looks like it failed because of the second disk failure.
I'm suggesting that you test the disks with Seatools, because it is useful to know exactly what the disk health issues are. You might also have issues on the other two disks (since the disks are generally put into the NAS together, and operate together, they often can fail in rapid sucession). If disks aren't 100% dead, it is often useful to clone them to working new drives. Sorting this out up-front helps steer the data recovery approach.
If one of the failing drives are still (mostly) readable, you could attempt to clone it to a new drive. You then could boot the system with the clone. There would likely be some file system corruption, but there's a good chance you'd recover most (maybe all) of the files.
Another approach here is to use RAID recovery software (for instance https://www.r-studio.com/ ), or to use Netgear's data recovery service ( https://kb.netgear.com/69/ReadyNAS-Data-Recovery-Diagnostics-Scope-of-Service ).
Ahh, I think I'm seeing your troubleshooting logic here. Just so I understand what happened here, please confirm my thought pattern (humor me please).
Disk 4 reported errors, so I went and hot swapped it with a new drive.
The X-RAID rebuild kicked off, but during the process, disk 3 probably failed.
Since the rebuild process probably didn't completely finish, I now have 2 failed disks in this array, which is more than the allowed number of failed disks (1).
Therefore, the troubleshooting path is to check all 4 of the old disks with Seatools in order to confirm the status of each drive (making sure to power off the NAS, pull each drive out and label which disk is which). If I can determine that 3 of the disks are still viable (presumably disk 1, disk 2 and possibly the old disk 4), could I pop the old disk 4 into the NAS and boot it up? Would that overwrite any data, or would that give me a shot at recovering some or all of the data that resided on the array, now that I have 3 working disks in there?
If it does turn out that disk 3 and the old disk 4 are no longer viable, I could theoretically attempt to clone them, and then pop them back into the NAS. If that fails, I'm stuck with either using recovery software as you suggested, or possibly paying for data recovery.
Does that cover the gist of it?
Appreciate the help StephenB.
I performed a short generic pass test on all 4 of the original disks, and they all passed. Should I do the long generic test too? At this point, should I attempt to get new drives and clone the original ones? Would the new drives have to be same size as the original (2 TB)?
bolan1 wrote:
Does that cover the gist of it?
Yes. One thing to keep in mind is that the old disk 4 might be out of sync with the rest of the array. There could be some writes that were lost when the NAS detected it had failed (and of course any writes to the volume after the disk was removed were also lost). So ideally recovery would be based on the other three disks.
bolan1 wrote:
I performed a short generic pass test on all 4 of the original disks, and they all passed. Should I do the long generic test too? At this point, should I attempt to get new drives and clone the original ones? Would the new drives have to be same size as the original (2 TB)?
I would run the long test, and also look directly at the SMART stats. Another thing you could try cloning from each of the three drives to your new one - looking for read errors during the process. That would give you some additional diagnostic information. That does destroy the data on your new drive of course - which probably doesn't matter, since the resync failed.
If you aren't certain which disk failed during the resync, then it would be best to clone the other three drives. Overall, cloning all the disks gives you a fallback if the data recovery attempts to more damage. You need to clone the drives using a utility that does sector-by-sector copying. Some of these utilities are more aggressive on re-trying failed reads than others. It's hard to say whether that's good or bad - the retries might give you more data, but they might also accelerate the drive failure.
You might be able to get away with cloning to larger drives, but one risk there is that the NAS might attempt to expand - which would only make recovery more complicated.
So I'd suggest sticking with 2 TB drives if you want to try booting the NAS with the cloned drives. If you want to use RAID recovery software then you could go with larger drives.
Once you have the clones, you can try booting the NAS with some combinations - for instance, with disks 1,2,3 and then disks 1,2,4; disks 1,3,4; and finally 2,3,4. You'd power down the NAS, put in the drives, and then boot. Power down before trying the next set. It's best to use the boot menu option to avoid file system checks and repair attempts. Also, put the disks in their original slots.
If the NAS does boot (giving you access to the files), then back up the data immediately. Don't try to resync, and don't write to the data volume.
Thanks for the information. In terms of cloning, can I use a offline drive duplicator dock, or should I use some sort of special software to do it (presumably connect the old disk and new disk via USB docks on a Windows PC, and use the software to clone)?
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