Adding new disks


To try rockstor I started by adding one disk as a “single” but now I wanted to add new one to expand the size of the pool but I get the error:

Pool migration from single to single is not supported.

How can I add a new disk to my single configuration?
Can I delete the pool and create a new? What happens to the data I already have there?



Dont take this answer to seriously, because i’m also just starting with rockstor and BTRFS.

But doesn’t the error mean that you are trying to move from one disk to another?

I guess you want to expand the pool, but add in redundancy.
can you create a RAID1? by adding the second disk?

What I want is to two disks working as a single unit, without redundancy in this case (the disks have different size).

You bring up a very good point @lightglitch.

Are the drives same size? If so, just create a raid0 pool. You will essentially get full capacity(2 x disk_size) without any redundancy. You can also try the resize feature to go from single -> raid0, if you choose not to delete the Pool and start over.

Now, if the drives are of different size AND you do not want any redundancy AND want to use full capacity (size1 + size2), then you can technically put them in a single pool(btrfs allows it). This feature, however, is not supported currently in the web-ui. I have created an issue to track this request, so we’ll get to it.

Thx, the second option was what I wanted.

Can I do it by using some linux commands?
Can you give-me some pointers on how to do it or where to look for it.

Since you are getting into administering btrfs manually, I strongly suggest you familiarize yourself with btrfs to a good extent. BTRFS wiki is a good start.

to create a 2 disk single Pool with name mypool and disks sdx, sdy and sdz, run mkfs.btrfs -m single -d single /dev/{sdx,sdy,sdz}. Then go to the web-ui and hit Rescan on the disks page. You’ll see two small buttons next to sdx,sdy and sdz in the table. Click on the import button of any of those disks and Rockstor will pick up the manually created “mypool”. You can create shares, snapshots etc… like any other pool but obviously pool ops like resize will not work as expected.


My goal is to add the new disk to the pool already created by rockstor web-ui, let’s see if it works.

@suman It was really simple to add the disk to the existing pool and after the “rescan” it shows both disks being used as a single. But the size of the pool it not update in the web interface, only shows the size of the original disk.

EDIT: After a reboot everything appeared with the correct values