Something I never had before.

I did upgrade a 6 TB to a 18 TB disk7: Stopped array, replaced the old 6 TB disk with a new 18 TB disk, started array. After restart the array told "No or unmountable file system". So I did restart the array again. That's what I do see now:

The new disk is in the array but disabled. Is this disk DOA?

towervm02-diagnostics-20251029-1707.zip

Did you follow the documented procedures for replacing disks?

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

SMART for disk7 looks fine, and emulated disk7 is mounted with plenty of data.

Check connections, SATA and power, both ends, including splitters.

Are you sure you have enough power for that many disks?

6 minutes ago, itzfantasy said:

Did you follow the documented procedures for replacing disks?

Sure. I guess it's my 50 th replacement in these servers in 17 years with Unraid.

5 minutes ago, trurl said:

Check connections, SATA and power, both ends, including splitters.

Are you sure you have enough power for that many disks?

Thanks for your answer.

It's one of my three Supermicro SC846 with BPN-SAS2-EL1 backplane. Systems are running since years that way.

1. Is there a way to tell Unraid to forget that disk7, put it in as a "new" replacement disk again, and start rebuild again?

2. What I don't understand. If this disk is disabled, how does it report SMART values. Is it really disabled or not? That puzzles me.

When I did start rebuild for the first time, I had 7 errors within 3 minutes, before I did realize that replacement went wrong this time. So I fear that this did destroy parity.

1 hour ago, hawihoney said:

Is there a way to tell Unraid to forget that disk7, put it in as a "new" replacement disk again, and start rebuild again?

You can rebuild on top, but make sure the emulated disk is mounting and the contents look correct before doing that:

https://docs.unraid.net/unraid-os/using-unraid-to/manage-storage/array-configuration/#re-enabling-a-disabled-disk-rebuilding-onto-itself

1 hour ago, hawihoney said:

What I don't understand. If this disk is disabled, how does it report SMART values. Is it really disabled or not? That puzzles me.

The disk is still connected, just disabled. If the disk dropped offline, then there wouldn't be SMART.

14 hours ago, JorgeB said:

You can rebuild on top, but make sure the emulated disk is mounting and the contents look correct before doing that:

https://docs.unraid.net/unraid-os/using-unraid-to/manage-storage/array-configuration/#re-enabling-a-disabled-disk-rebuilding-onto-itself

Yes, that did the trick. Thanks a lot. Rebuild is running - fingers crossed.

I do have a backup disk (the one that was replaced). After rebuild I will copy it's content over the new one. Just to fix the 6 errors that found their way into the parity during the initial problems.