Hello, I am a newbie to Unraid.
 

Currently, my pool consists of two 4TB SSDs configured in RAID1.

I wanted to remove one disk and keep only a single disk in the pool.
 

I followed these steps:

(1) Stopped the array

(2) Removed one disk from the pool

(3) Changed the allocation profile of the remaining disk to "Single"

(4) Changed the slot count to 1 and started the array
 

However, I keep seeing the following error message:
"Cache pool BTRFS missing device(s) SSD 4096G (nvme1n1)"
 

Additionally, the slot count reverted to 2, and the SIZE is displayed as 8TB instead of 4TB.
 

How can I ensure that the remaining pool operates normally?
 

Thank you.

That's not how you do it, but are you running v6.12 or v7.0? Btrfs device removal in the latter is not currently working, but I can tell you the steps to do it manually, but in any case, please post the diagnostics.

11 hours ago, JorgeB said:

That's not how you do it, but are you running v6.12 or v7.0? Btrfs device removal in the latter is not currently working, but I can tell you the steps to do it manually, but in any case, please post the diagnostics.

Oh, I forgot to mention the version—it's 7.0.0.
If I had known about the diagnostics feature, I would have saved the logs beforehand, but I already solved the issue in a rather foolish way.
Fortunately, I hadn't moved any files to the array yet, so I just backed up the pool, formatted it, and started over with a new config.
For future reference, could you provide the manual procedure?

Assuming the pool was raid1, first convert to single using the GUI, then manually remove the device:

 

btrfs dev del /dev/sdX1 /mnt/<pool_name>

 

When done, reimport the pool with the remaining device.