Setup-Storage: how to specify multiple btrfs subvolumes?

[Kerim Gueney]

Hey Urs,

> I had just assumed that the btrfs itself is specified like a "normal" 
> filesystem partition and wrote:
>
> primary /      10G-30G   btrfs  rw
That sounds like a good feature request actually. When we worked on the 
btrfs feature, we focused on the raid functionality. Might have even 
falsely assumed that nobody would use btrfs in a single disk configuration.

> By looking at the source, I found that "single" is also a valid choice 
> here.
> http://fai-project.org/doc/man/setup-storage.html only gives one btrfs 
> example, and no formal description of what the btrfs lines should look 
> like.
Just replace "raid*" with "single" . I suggest you take a look at this:
https://btrfs.wiki.kernel.org/index.php/Using_Btrfs_with_Multiple_Devices

For single devices using "single" for data and the defaults for metadata 
is suggested. However, please note that "single" does not simply stand 
for "single device", for data it is actually like raid0 but with 1Gb 
stripes and for metadata it means that metadata won't be duplicated.

> One more thing: the regex matching btrfs-lines in setup-storage 
> strictly matches spaces after the btrfs token. Maybe that should be 
> changed to "\s"?
Good idea. I'll fix it soon!


Best regards
Kerim