Advice on rectifying failure please

[anthropoidape]

Hi all, I have just had an unexpected failure.

 

I had this array, all good:

 

 

When I recently replaced disk 6 (successfully, no problems at all) I noticed that Disk 7 is not only old but slow. Therefore I bought a new 4tb drive to gain speed and some more space.

 

I added that drive just now, in place of disk 7.  I did this while unraid was shut down of course. I will call that shut down Timepoint A. 

 

As I commenced the array rebuild, disk 4 failed, with unraid stating that it doesn't have a readable file system. SMART attributes show UDMA CRC error counts, so I have replaced and reseated cables etc.

 

The problem I have is that since I did start the rebuild on the new disk 7, unraid now thinks that both disk 4 and disk 7 are new disks. Even if I put the old disk 7 (the 2tb drive) back on, it sees that as a new disk as well. So now it tells me I have too many wrong/missing disks. 

 

It seems to me like I should be able to put the array back as it was and rebuild disk 4, as nothing should have been written to any of the drives since Timepoint A, except for maybe some attempted writes to the new disk 7 that is not involved in the rebuild I want to do.

 

Am I right, and if so how do I make unraid accept the disks as correct (ie specify parity, d1, d2, d3, d5, d6, and d7 as good and treat d4 as new)? 

Otherwise, what's my best bet here? There is over 3tb on disk 4 that I'd rather not lose if possible. 

[anthropoidape]

Apologies, the precise error is: "Unmountable: Wrong or no file system"

[anthropoidape]

To reply to myself again - I have mounted both the old disk 4 and the old disk 7 in unassigned devices and they both seem to be perfectly readable with no data loss. 

 

Therefore it seems like I should recreate the old array, disks 1 to 7, and then rebuild parity based on the actual disk contents. Is that right? I am not going to do anything just now as I have to do some other stuff. Would appreciate suggestions. 

 

Sorry about the multiple posts, you know how initially you kinda panic right

[anthropoidape]

Okay rebuilding parity as all data drives seem to be intact. After that I'll do the disk swap that was the original plan. 

 

I am not really clear on what went wrong, still scratching my head a bit.

[Vr2Io]

3 hours ago, anthropoidape said:

Therefore it seems like I should recreate the old array, disks 1 to 7, and then rebuild parity based on the actual disk contents. Is that right?

Yes, if org. disk confirm mountable.

Edited November 26, 2022 by Vr2Io