On Wed, May 09, 2012 at 03:37:35PM +0100, Hugo Mills wrote:
> On Wed, May 09, 2012 at 04:25:00PM +0200, Helmut Hullen wrote:
> > Du meintest am 07.05.12:
> >
> > [...]
> >
> > >> With a file system like ext2/3/4 I can work with several directories
> > >> which are mounted together, but (as said before) one broken disk
> > >> doesn't disturb the others.
> >
> > > mkfs.btrfs -m raid1 -d single should give you that.
> >
> > Just a small bug, perhaps:
> >
> > created a system with
> >
> > mkfs.btrfs -m raid1 -d single /dev/sdl1
> > mount /dev/sdl1 /mnt/Scsi
> > btrfs device add /dev/sdk1 /mnt/Scsi
> > btrfs device add /dev/sdm1 /mnt/Scsi
> > (filling with data)
> >
> > and
> >
> > btrfs fi df /mnt/Scsi
> >
> > now tells
> >
> > Data, RAID0: total=183.18GB, used=76.60GB
> > Data: total=80.01GB, used=79.83GB
> > System, DUP: total=8.00MB, used=32.00KB
> > System: total=4.00MB, used=0.00
> > Metadata, DUP: total=1.00GB, used=192.74MB
> > Metadata: total=8.00MB, used=0.00
> >
> > --------------------------------------
> >
> > "Data, RAID0" confuses me (not very much ...), and the system for
> > metadata (RAID1) is not told.
>
> DUP is two copies of each block, but it allows the two copies to
> live on the same device. It's done this because you started with a
> single device, and you can't do RAID-1 on one device. The first bit of
What Hugo said. Newer mkfs.btrfs will error out if you try to do this.
> metadata you write to it should automatically upgrade the DUP chunk to
> RAID-1.
We don't "upgrade" chunks in place, only during balance.
>
> As to the spurious "upgrade" of single to RAID-0, I thought Ilya
> had stopped it doing that. What kernel version are you running?
I did, but again, we were doing it only as part of balance, not as part
of normal operation.
Helmut, do you have any additional data points - the output of btrfs fi
df right after you created FS or somewhere in the middle of filling it ?
Also could you please paste the output of btrfs fi show and tell us what
kernel version you are running ?
Thanks,
Ilya
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