ReadyNAS Duo freezes during resync - what to do?

Do you have a backup of the data on the NAS?
Do you have a Duo v1 or v2?
http://www.rnasguide.com/2012/01/09/how ... -or-nv-v2/
Do you know which drive had the errors?

Don't pull the drive out while the NAS is on and resyncing. One of your options would be to power down and try to boot the duo with the good disk in, then if you can access the data back it up before doing anything else.

I would initially wait a few more hours to see if any progress is being made.

I use this NAS to backup my other NAS (ReadyNAS Ultra), so you could say it's no diaster if I loose the contents (as long as my other NAS behaves).
I don't know if it's a v1 or v2, it says RND2110 v2, FW V4.1.6. But according to the linke you provided, it's a v1 based on the outline of the rear. Does it matter?

The first email message I got was that Disk 1 had an increased reallocated sector count from 0 to 1, and a warninbg that thius may indicate that the drive will fail soon. "If the errors continue to increase, you should be prepared to replce the disk." About an hour later I received several messages saying that "Access to the disk on channel (??) is producing I/O errors. ALthough the array is still redundant, please replace the drive as soon as possible, as it is likely to fail soon."

A little while later I got a message saying "A SATA reset has been perfomred on one or more of your disks that may have affected the RAID parity integrity. It is recommended that you perform a RAID volume resync."

I felt quite safe by getting these seemingly hand-holding messages, but alas, the drive just forze after on hour or so of resyncing.

I will follow your suggestion to power down and pull out disk 1 (which is the most likely suspect based on the messages I got). Do I need to move disk 2 to slot # 1 after pulling the #1 disk?

lenscooter wrote:
I don't know if it's a v1 or v2, it says RND2110 v2, FW V4.1.6. But according to the linke you provided, it's a v1 based on the outline of the rear. Does it matter?

Running 4.1.6 means it is a v1 for sure. The link explains the mismatch on the back label. There are differences between the platforms, so it does matter when providing advice.

BTW 4.1.6 is very old firmware. After you fix your disk issues you should update it.

I will follow your suggestion to power down and pull out disk 1 (which is the most likely suspect based on the messages I got).

lenscooter wrote:
Do I need to move disk 2 to slot # 1 after pulling the #1 disk?

No.

That reference to 4.1.6 is probably on a sticker on the rear. The firmware may have already been updated but it is a good idea to check. Latest is currently 4.1.13

If it's a backup NAS, you could just wait until you have a new disk. Boot without the faulty disk then hot add the new disk to slot 1.

Thanks for good advice. The immediate problem now is that the unit does not respond to the on/off button, regardless of the time I press it or the number of times I press it. The Duo has been chewing for about 30 hours now, and I cannot get it to stop.

So now my question is: is it better to unplug the power cord, or to hotswap the faulty disk while the NAs is stuck in this endless loop of disk activity?

I think you may need to unplug the power cord.

Since this is purely a backup NAS, even if it fails totally you can do a factory reset, and bring it back to life and simply re-copy the data. So it might not matter which you try.

I'd be tempted to remove the faulty disk, and see if the NAS recovers.

If it does, then you could hot-insert the replacement.
Otherwise pull the plug.

Let us know how it works out.

This is how it worked out:

Regardless of what I did (booting with one or the other or both drives) I could not get the Duo back on track. I decided to check both drives with WD Data Lifguard Diagnostic, and it turned out that one had partitions but didn't pass the diagnostic test (massive read errors and solid red SMART test) while the other drive was free of faults but completely blank (no partitions or file system).

My conclusion is that doing a resync (as I did because that was what my Duo told me to do) is probably not a good idea when there is one bad drive in the system. I feel truly disappointed with the ReadyNAS Duo, since the first time my redundant and hotswappable unit has a disk failure, I lost all my data. If one bad disk leads to the other disk being wiped clean, the system doesn't work as it should.

I now made a factory reset with the fault-free drive and am waiting for my newly ordered drive to arrive Monday before making a fresh backup of my other (Ultra) NAS.

Thanks for yout support here, appreciated!

That apparently "blank" disk was the parity disk with no partition table on it.

So while it appeared to be blank it wasn't.