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

[Hugo Mills <hugo@carfax.org.uk>]

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On Sun, May 06, 2012 at 09:49:36PM +0200, Alexander Koch wrote:
> 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.

   Yes, that all looks good.

> > 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?

   The space is automatically allocated as it's needed.

   Hugo.

-- 
=== Hugo Mills: hugo@... carfax.org.uk | darksatanic.net | lug.org.uk ===
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