Ok...

Should am I good to just re-start the array with the new drive in disk 4 and resume normal operation? Obviously my files are missing but is the rest ok?

If you want to have a drive you can use with UFS Explorer (since the original seems to be seriously broken) you need to rebuild the unmountable disk4 to get a drive you can read with UFS Explorer.

If you don't want to bother with UFS Explorer, you still need to rebuild something to get the array back in sync.

• You can rebuild the unmountable disk4 onto the replacement. That will get the array back in sync, then you can format disk4 so it will be a new empty XFS filesystem.

• You can New Config with the replacement disk4, let parity rebuild, then format disk4 so it is a new empty XFS filesystem.

• You can New Config with nothing assigned as disk4 and let parity rebuild. Then you won't have a disk4 as part of the array.

Also note that however this turned out, you still lost any files that were written to (emulated) disk2 since it became disabled.

10 hours ago, ActionJackson said:

I think this disk 2 has been disconnected for some time. I'm not seeing any files on it that have a datestamp of 30 days or newer

1 hour ago, trurl said:

Setup Notifications to alert you immediately by email or other agent as soon as a problem is detected.

Ok, sorry i'm not entirely sure what my options here are. My intent is to use the new disk in the disk 4 slot, but I want to try to bring back any data that I might be able to. Right now I'm attempting to load up UFS explorer with the broken disk 4 from before, but I have to get ubuntu installed on another machine so that will be a bit. If that doesn't work, are you saying there's a way to use this new disk to attempt to put something on it that would be readable by UFS explorer? If that's the case that's what I want to do. Is that something you can help with?

26 minutes ago, ActionJackson said:

have to get ubuntu installed on another machine

Why? UFS Explorer will run on Windows.

26 minutes ago, ActionJackson said:

use this new disk to attempt to put something on it that would be readable by UFS explorer

Go ahead and rebuild the unmountable contents of the emulated disk4 to the drive.

Stop the array, assign disk4, start the array to begin rebuild.

After rebuild completes, you can shutdown, remove disk4, and see if UFS Explorer can do anything with it. And whether it can or not, you still have the array back in sync with the new drive as long as you don't change it in any way while it is out of the array.

Why? UFS Explorer will run on Windows.

it doesn't seem like Windows will read XFS filesystems? That was my understanding

Go ahead and rebuild the unmountable contents of the emulated disk4 to the drive.

I'm not sure how to do this, do you have a guide?

3 minutes ago, trurl said:

you still have the array back in sync with the new drive as long as you don't change it in any way while it is out of the array.

And as long as you don't start the array either, since it will work just fine emulating the missing disk but mounting any disks in the array without that disk will make the array out-of-sync with the missing drive.

Not a big deal since you can always get the array back in sync in any of those ways I mentioned before.

I'm sorry I'm such a noob to this but it still isn't clear to me what I need to do to try to rebuild this disk. I don't want to make a mistake :(

10 minutes ago, ActionJackson said:

it doesn't seem like Windows will read XFS filesystems? That was my understanding

I've never needed to use UFS Explorer, but as far as I know from other users, Windows UFS Explorer will still try to work with XFS.

2 minutes ago, ActionJackson said:

what I need to do

The array is waiting for a disk to be assigned as disk4 so it can rebuild it. This is basically how rebuild always works. You assign a replacement, or reassign the same disk, start the array, and it will rebuild to that disk. Here is the long version in the docs:

https://docs.unraid.net/unraid-os/using-unraid-to/manage-storage/array/replacing-disks-in-array/

The short version is what I said before:

11 minutes ago, trurl said:

Stop the array, assign disk4, start the array to begin rebuild

Actually this is a better link:

https://docs.unraid.net/unraid-os/using-unraid-to/manage-storage/array/replacing-disks-in-array/#replacing-faileddisabled-disks

since it skips over the stuff about upgrading capacity. That part definitely doesn't apply to your situation.

ok great. thank you. I did that, and I'm getting mixed messages. I got an alert sayings its reconstructing but it's also saying unmountable

Of course it's unmountable. Rebuild writes the exact contents of the emulated disk, and the emulated disk is unmountable. That is why we always try to repair before rebuild, but repair wasn't working for you, so we are hoping UFS Explorer can recover something from the unmountable rebuild.

As for that first message, the only "normal operation" available for an unmountable disk is format, not what we want to happen right now.

ok so should i stop it? or jsut let it go

Rebuild is what we want, let it finish. Then

41 minutes ago, trurl said:

After rebuild completes, you can shutdown, remove disk4, and see if UFS Explorer can do anything with it

ok, great. what sort of indication will I have when its done

You will see in MAIN - Array Operation. Right now it tells you it is rebuilding.

2 minutes ago, trurl said:

emulated disk

Parity doesn't know anything about filesystems. It is all just a bunch of bits. Parity is not a backup, it contains none of your data. The parity algorithm allows the contents of a missing disk to be calculated by reading parity plus all other disks.

Parity is basically the same concept wherever it is used and however it is implemented. A lot of this makes a lot more sense if you understand parity. It is really very simple. If you are interested follow this link

https://docs.unraid.net/unraid-os/getting-started/what-is-unraid/

then expand the Software-defined NAS section, and then expand the How Parity works section.

says 6 hours, see you this evening lol

Do you have another copy of anything important and irreplaceable?

1 minute ago, trurl said:

Parity is not a backup, it contains none of your data.

Plenty of much more common ways to lose data besides a failed disk, including user error. Letting the array run degraded until another disk fails might qualify as user error.

oh it's ABSOLUTELY my fault. I'm not pretending it isn't. I definitely dropped the ball here. Most of the data is replaceable, some of it may not be, but it also may not be that important. I wish I had a list to know for certain, so I will be implementing status alerts and regular offsite data backups (not all the data, just metadata really) to help me moving forward. Most of (if not all) of the critical stuff is not stored on this drive.

3 minutes ago, ActionJackson said:

says 6 hours, see you this evening lol

Might be a little longer than that. It starts at the longer (so more data) outer tracks and works toward the shorter (so less data) inner tracks, but the RPM is constant so inner tracks are slower data rate. In other words, expect it to slow down some as it progresses.

You should see lots of writes to rebuilding disk, lots of reads from all other disks, and zeros in the ERRORS column for all disks. If there seems to be a problem before it completes, post new diagnostics.

almost done, at 93%, but not something you want to see:

storemore-diagnostics-20260310-1929.zip

31 minutes ago, ActionJackson said:

almost done, at 93%, but not something you want to see:

storemore-diagnostics-20260310-1929.zip

Once it's done disk4 is going to be unmountable. you will want to shutdown the system and then put disk4 into a windows pc and use UFS explorer to read the disk. If it can read the disk you may be able to copy the contents from the disk to your PC to put back on your NAS

On mobile now will look at diagnostics soon to see why the errors for disk 2

I am now running UFS explorer and doing a storage scan. I only selected XFS and did not do a content search, I left everything else to default. While that runs, is there any harm in starting my array with the 3 drives? I have a 4TB I would like to install as a new parity drive, and depending on what is going on with that disk 2 I may need to replace it with my current 3TB parity drive.