I'm running the latest Unraid 6b15.

 

I've added an SSD to my Unraid box, and then I proceeded to add the SSD as a cache drive and subsequently setup a BTRFS cache drive pool with my previously existing cache drive.

 

My question is - how do I now safely remove the SSD from the cache pool without losing any information on my original cache drive???

So you currently have two disks in the pool, correct?

 

First, as a matter of precaution, run a balance (this can be done from the cache device page by clicking balance).  It will take some time to complete and you can refresh the page to check status. When complete, stop the array and unassign whichever device from the pool you want to remove. Then drop the assignable slots down to 1 and start the array.

jonp, I went ahead and followed your instructions.

 

Now I'm getting a message that my original cache drive is unmountable because it is bound to a btrfs pool.

 

Did I miss something???

jonp, I went ahead and followed your instructions.

 

Now I'm getting a message that my original cache drive is unmountable because it is bound to a btrfs pool.

 

Did I miss something???

Which "original" drive are we talking?  The one in the pool or the one you removed?

jonp, I went ahead and followed your instructions.

 

Now I'm getting a message that my original cache drive is unmountable because it is bound to a btrfs pool.

 

Did I miss something???

Ok, instead of reducing the number of cache slots to 1, leave it assigned at 2. Then start the array and a rebalance should occur that converts the raid1 pool to a single.

jonp, I went ahead and followed your instructions.

 

Now I'm getting a message that my original cache drive is unmountable because it is bound to a btrfs pool.

 

Did I miss something???

Ok, instead of reducing the number of cache slots to 1, leave it assigned at 2. Then start the array and a rebalance should occur that converts the raid1 pool to a single.

 

Good day Jonp!

 

I'm in the same boat as MasterC. I've originally had one single cache drive (1TB WD Black) and I've recently purchased a 500GB SSD hoping to improve VMs/Dockers performance. I've mounted the SSD as a second cache drive and it seems to have created a raid pool of some sort. Now, I was hoping to remove my 1TB WD Black HDD and only use my 500GB SSD but when I try your suggested method by stopping the array, unassigning the Cache #1 (1TB WD Black), the cache won't mount anymore and it' shows "Unmountable" in my Cache section of Unraid.

 

I was under the impression a rebalance would occur once removing the other but sadly, it doesn't.

 

Is there a proper way to remove the 1TB WD Black HDD and only have the 500GB SSD without losing what's on the Cache drives?

 

Thanks and have yourself a great day!