Splitting Cache Pool (Going from large cach (with 2 drives)) to smaller cache (with RAID1)

[TexasDave]

Happy 2023!

I am doing some yearly maintenance and want to split my cache pool. All is fine I just do not think I need that big of a cache and would prefer the redundancy of splitting it.

It is a pool of two devices - see attached.

There are two excellent threads on doing this.

Thread One is here. This is done using the GUI. When I do this (see screenshot), fill in the fields as directed (to RAID1) and click "Balance" it returns instantly which I am sure is not right. And looking at my Shares - the Cache has not been split.

Thread Two is here in the unRAID FaQ. I then try to do it on the CLI. I execute:

 

btrfs balance start -dconvert=raid1 -mconvert=raid1 /mnt/cache

 

and this took about 60 minutes. But again - I am not seeing a change. See screenshot.

I am sure it is "pilot error" and would appreciate a pointer as to what I am doing wrong?

Many thanks!!

[JorgeB]

20 minutes ago, TexasDave said:

the Cache has not been split.

What do you mean split? Pool was convert to raid1 so now it's redundant, that's expected behavior.

[itimpi]

If you mean that you want to go down to a single drive in the cache, then now that you have converted to raid1 (so that data is on both drives) you can now stop the array, remove one of the cache drives and start the array again.   You now set the profile for the cache to be Single (if it has not been done automatically after removing the drive).   Note that there is now no redundancy in the cache so if it fails it’s contents will be lost.

[TexasDave]

Thanks both - as it "came back instantly" from the GUI, I was afraid something was not working. And I guess I thought the GUI would show something different. Thanks!