Bit of background, this started with this thread:

DATA REBUILD GOING AT LESS THAN 10 MB/S

 

Turns out, it's not the cable. I'm beginning to suspect a faulty SATA port on the motherboard. The rebuild that I said was working at 150 mb/s ended up slowing down to 2-6 mb/s after a couple hours.

 

My array is currently:

Parity - 6tb, healthy

Disk 1 - 3 tb, healthy

Disk 2 - 3 tb, healthy

Disk 3 - 3 tb, Current pending sector: 6 error

Disk 4 - 3 tb, Read error, contents emulated

 

Before beginning any of the troubleshooting in the last post, I used unBalance to move all the contents from disk 4 to disks 1, 2, and 3 (3 was showing healthy at the time, the only issue then was the read error).  It appears to have been successful, but there were still a few gigabytes showing as being on disk 4 (if I lose what's left there, I won't be too bothered; it wasn't of critical importance).

 

As my troubles progress, I've become more concerned about disk 3 than disk 4, given disk 4's mostly empty state...but there isn't room on 1 & 2 to empty disk 3, and I know if I try to replace & rebuild it, that'll bork parity.

 

So my question is - can I leave disk 4 emulated for the moment, and add the disk that I was replacing it with to the array as disk 5 in order to empty the contents of disk 3?  At that point, there wouldn't be much use in rebuilding disks 3 or 4, so I could just use the proper procedure to shrink them out of the array.

 

Thanks for your input

Attach diagnostics to your NEXT post in this thread.

Apologies, didn't think that'd be necessary for a hypothetical "will this work" question. Here they are.

 

I have already begun the preclearing process on the disk that I am looking to add as disk 5.  It is the same disk that I was trying to rebuild disk 4 to, which was only rebuilding at 2-6 mb/s.  It has been preclearing most of the day, fluctuating between 90-150 mb/s, so the speed problem doesn't seem to reside on that disk (it is also plugged into a different SATA port on the motherboard than it was previously).

tower-diagnostics-20230102-1743.zip

26 minutes ago, justinporteus said:

used unBalance to move all the contents from disk 4 to disks 1, 2, and 3

Not really recommended. It is just making everything work that much harder when your array is already unprotected. Rebuild is the way to handle a disabled disk. If you really feel the need to backup something from the emulated disk before attempting rebuild, then copying (not moving) it somewhere OFF the array would be the best approach, that way nothing in the array is changed while you are unprotected.

 

Not at all clear how you got to this point. Looks like Unraid thinks added disk5 is already part of the array. When you have single parity, you can't add a disk when you already have a disabled disk.

 

You are having connection problems with disk5.

 

I don't see anything assigned as disk4 currently.

 

And maybe it is trying to clear disk5??? Which is what it would do if you added a disk that wasn't already clear. Just don't see how it let you add a disk5 if disk4 was already disabled.

 

All very confusing.

 

Post a screenshot of Main - Array Devices and a screenshot of Main - Array Operation.

5 minutes ago, trurl said:

Not really recommended. It is just making everything work that much harder when your array is already unprotected. Rebuild is the way to handle a disabled disk. If you really feel the need to backup something from the emulated disk before attempting rebuild, then copying (not moving) it somewhere OFF the array would be the best approach, that way nothing in the array is changed while you are unprotected.

The problem is, I don't have anywhere off the array that is large enough to store everything.

 

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Not at all clear how you got to this point. Looks like Unraid thinks added disk5 is already part of the array. When you have single parity, you can't add a disk when you already have a disabled disk.

I assigned the disk 4 replacement disk as disk 5 in order to begin the clearing procedure (as explained in the post where I included my diagnostics); I probably should have posted before beginning that, but it didn't occur to me that it might be an issue until now.  And I did add it after disk 4 had already been disabled - unraid didn't give me any issue with it.

 

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You are having connection problems with disk5.

Well...sh*t. It's a brand new disk, and it's plugged into a different SATA port than when it was rebuilding slowly, and with a different cable. Should I be looking at RMAing it?

 

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I don't see anything assigned as disk4 currently.

No, like I said, its contents are emulated, and I'm using the disk that was supposed to become disk 4 as the potential data dump disk.

 

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And maybe it is trying to clear disk5??? Which is what it would do if you added a disk that wasn't already clear. Just don't see how it let you add a disk5 if disk4 was already disabled.

Yes, I already mentioned that I had begun the clearing process.

 

Quote

Post a screenshot of Main - Array Devices and a screenshot of Main - Array Operation.

Yep, posting screenshot now...but as I was typing this, the disk clearing process errored out because of a read error (good call 😂😭), so it is no longer showing as doing anything.  Also feels weird that it would get cancelled because of a read error when my understanding is that it's a writing operation? The disk is reporting zero reads, so that seems...wrong.

Stop the array, unassign disk5, start array, stop array, power down, replace disk5 cables and post new diags after array start.

13 hours ago, trurl said:

When you have single parity, you can't add a disk when you already have a disabled disk.

On second thought, I can't really think of a reason Unraid shouldn't let you add any number of cleared disks to an array in this situation. They aren't going to affect parity. Can someone confirm?

 

Even if it will, I can't think of a good reason to do it when you have more important things to deal with. Adding disks to the array won't help anything. If you need to backup some data from a failing array you don't want to do it on that failing array.

1 hour ago, trurl said:

On second thought, I can't really think of a reason Unraid shouldn't let you add any number of cleared disks to an array in this situation. They aren't going to affect parity. Can someone confirm?

Yes, you can still add new disks, as long a not trying to a rebuild at the same time.

15 hours ago, justinporteus said:

The problem is, I don't have anywhere off the array that is large enough to store everything.

Which brings up this question.

 

Do you have another copy of anything important and irreplaceable? Parity is not a substitute for backup.

2 hours ago, trurl said:

Which brings up this question.

 

Do you have another copy of anything important and irreplaceable? Parity is not a substitute for backup.

Everything that is important enough to be more than an inconvenience if lost is backed up on the cloud.  Everything not backed up is a level of importance where it would be annoying to lose, but I'm a data hoarder, so it's mostly just archival stuff for work I've done over the last 6 years and will likely never revisit.

 

6 hours ago, JorgeB said:

Stop the array, unassign disk5, start array, stop array, power down, replace disk5 cables and post new diags after array start.

I ended up shrinking the array down to the two good disks and parity.  Parity is rebuilding at the moment, and it looks like I've suffered minimal data loss (some very recent files are missing, but everything else seems to be accounted for).

 

Disk 3 is going to be discarded due to smart reports.

The original disk 4 I am going to check in another machine using tools I am more familiar with to see whether the problem was with the disk, or just with the cable and/or motherboard.  If it's good, I'll think about adding it back into the array (I've been considering moving to an HBA card to expand capacity, so if there's a problem with the motherboard SATA ports, that should bypass it.)

Same for the new disk.  If it's also good, and the problem is with the cable/mobo, then yay I get 4 more TB of capacity.

 

Thanks for your help, I know I've done some stupid shit here that could have been avoided if I were more patient or thought things through better, and none of you made me feel like the impatient n00b that I am.

14 minutes ago, justinporteus said:

Disk 3 is going to be discarded due to smart reports.

The original disk 4 I am going to check in another machine using tools I am more familiar with to see whether the problem was with the disk

Unless those other tools are Linux might not be able to read the filesystems on those disks.

 

You could try those as Unassigned Devices in Unraid, repair filesystems if necessary, mount them Unassigned, and copy their files.