Re: btrfs-raid10 <-> btrfs-raid1 confusion

[Alexander Koch <lynix47@googlemail.com>]

Thanks for clarifying things, Hugo :)

>    It won't -- "btrfs fi df" reports what's been allocated out of the
> raw pool. To check that the disks have been added, you need "btrfs fi
> show" (no parameters).

Okay, that gives me

    Label: 'archive'  uuid: 3818eedb-5379-4c40-9d3d-bd91f60d9094
        Total devices 4 FS bytes used 1.68TB
        devid    4 size 931.51GB used 664.03GB path /dev/dm-10
        devid    3 size 931.51GB used 664.03GB path /dev/dm-9
        devid    2 size 1.82TB used 1.56TB path /dev/dm-8
        devid    1 size 1.82TB used 1.56TB path /dev/dm-7

so I conclude all disks are successfully assigned to the raw pool for my
'archive' volume.


> You're not comparing the right numbers here. "btrfs fi show" shows
> the raw available unallocated space that the filesystem has to play
> with. "btrfs fi df" shows only what it's allocated so far, and how
> much of the atllocation it has used -- in this case, because you've
> added new disks, there's quite a bit of free space unallocated still,
> so the numbers below won't add up to anything like 3TB.

So how is the available space in the raw pool finally allocated to the
usable area? Must I manually enlarge the filesystem by issuing a
'btrfs fi resize max /mountpoint' (like assigning space of a VG to a
logical volume in LVM) or is the space allocated automatically when the
filesystem gets filled with data?


Regards,

Alex