ReadyNas 516 suddenly stuck on 51% scrubbing

[Vinzz]

Hello,

My business nasbox (ReadyNas 516 running v6.*) suddenly stopped working and shows "Scrubbing 51.85%" on the front LCD screen. The device is completely unresponsive. Buttons on the device are not working

and I have no network connection (ssh, https, smb). This device is stuck for over a week now.

What is my best option here? Can I press the power button to reboot the device? Or will it get stuck again? Can I recover my data (worst case)?

Sincerely yours,

Vincent

[StephenB]

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@Vinzz wrote:

Can I press the power button to reboot the device?

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If ssh is enabled, you might first see if you can get access that way.  Note it is possible to cancel the scrub using ssh.

If not, then at some point you will have to.  If the display hasn't updated in a week, then there's not much point in delaying.

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@Vinzz wrote:

Or will it get stuck again? 

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It might.  Try 

1. removing one disk (label by slot)
2. boot in read-only mode

Assuming the NAS is using single redundancy, that combination should prevent the scrub from restarting and any further harm.  

Boot menu instructions are on page 120-121 here:

• https://www.downloads.netgear.com/files/GDC/READYNAS-100/ReadyNAS_%20OS6_Desktop_HM_EN.pdf

If the system boots, then grab the full log zip file from the web ui.  If the volume is mounted, then make a backup right away.

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@Vinzz wrote:

Can I recover my data (worst case)?

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It is at risk, and too early to tell.

[Vinzz]

Thanks for the information.

SSH was enabled. But the connection fails (the device is fully unresponsive). It does not respond on any protocol (even pings).

I will try and reboot the device today.

I'll also try to pull one of the drives out if necessary (Device is in single redundancy mode or x-raid mode)

[StephenB]

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@Vinzz wrote:

I'll also try to pull one of the drives out if necessary (Device is in single redundancy mode or x-raid mode)

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Try read-only mode first - I think that will prevent the scrub from starting again, so it might be enough.

The NAS uses mdadm to create virtual disk(s) for RAID, and which then are formatted to use the btrfs file system. Both mdadm and btrfs have scrub commands, and generally when the NAS says it is "scrubbing" it is running both in parallel. Not sure why Netgear does that, IMO it would be better to run them sequentially (and provide enough info so the user can see which scrub is running).

Booting read-only ensures that the btrfs file system is mounted read-only, so the btrfs scrub certainly can't be done.  I'm not sure if the mdadm virtual disk is also assembled read-only or not - so it is conceivable that the RAID scrub will resume.  Even if it does, the system might be responsive enough.

Note that booting normally w/o a disk would prevent mdadm scrubs, but it would not prevent btrfs scrubs.