Hi Kerim,
On 15/01/15 18:26, Kerim Gueney wrote:
Here is the promised config file. In this example I am using a single
disk with two different partitions one containing btrfs and the other
ext4 and with / in btrfs and /home in ext4:
disk_config disk1
primary /home 50% ext4 defaults
primary - 50% - -
disk_config btrfs
btrfs raid1 / disk1.2 noatime,subvol=@/
Ah, so that's how it works.
I had just assumed that the btrfs itself is specified like a "normal"
filesystem partition and wrote:
primary / 10G-30G btrfs rw
this, of course, also worked, but simply produced a plain brtfs with the
root in the / subvolume.
The subsequent btrfs lines then confused me. Maybe the documentation
should mention more explicitly that btrfs should *not* be initialized as
such, if any of the more advanced options are to be used?
The raid1 is in this case redundant, because btrfs uses raid1 for data
and metadata by default (irrc that's true even for single disk
configurations, because you can always add a disk later and it kinda
needs to know how to handle it). However, we decided to make that part
mandatory.
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.
Also note the "subvol=@/" , setup-storage will not create your / in the
root of the filesystem but actually create a subvolume for it. It will
be added to your fstab accordingly.
So that's it. You first define your partitions and the "classical"
filesystems in the "disk_config disk*" and then in disk_config btrfs
part, you define all btrfs raids/partitions. If you want both / and
/home in a subvolume each and each of them in their own paritions, then do:
disk_config disk1
primary - 50% - -
primary - 50% - -
disk_config btrfs
btrfs raid1 / disk1.2 noatime,subvol=@/
btrfs raid1 /home disk1.1 subvol=@/home
Ok, wonderful. All cleared up now.
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"?
Best regards
Kerim
Cheers, and thanks alot,
//Urs
