Re: Fwd: btrfs-tools backport for Debian Lenny

[Martin Steigerwald <Martin@lichtvoll.de>]

[-- Attachment #1: Type: Text/Plain, Size: 1700 bytes --]

Am Mittwoch 17 Februar 2010 schrieben Sie:
> On Wed, Feb 17, 2010 at 3:32 PM, Martin Steigerwald <ms@teamix.de> 
wrote:

Leaving Cc to backports-users mailinglist and Debian package maintainer 
dropped as its a technical BTRFS discussion.

> > Hi!
[...]
> > It basically works, but I am wondering it the RAID options work
> > correctly. I used:
> >
> > mkfs.btrfs -d raid1 -m
> > raid1 /dev/mango1/homelokal1 /dev/mango2/homelokal2
> >
> > on two 200 GiB logical volumes and get
> >
> > mango:~# df -hT /mnt/zeit
> > Dateisystem   Typ    Größe Benut  Verf Ben% Eingehängt auf
> > /dev/mapper/mango1-homelokal1
> >             btrfs    400G  101M  400G   1% /mnt/zeit
> >
> > Shouldn't that be 200GiB for a BTRFS Raid 1 setup?
> 
> this has been discussed several times on the list.

Sorry, I admit I follow BTRFS irregularily and main point in my mail was 
to announce the backport.

> Since btrfs file level redundancy policy, the proper way for it to
> behave is to show full physical capacity of the devices.
> Usage will be correctly accounted, so if you write a 100MB file in
> that raid1 FS tree
> the used space will indicate 200MB of additional used space.

Hmmm, that still doesn't match, cause I wrote a 100MiB file to the 
partition:

mango:~# dd if=/dev/zero of=/mnt/zeit/ddimg bs=1M count=100
100+0 Datensätze ein
100+0 Datensätze aus
104857600 Bytes (105 MB) kopiert, 0,313594 s, 334 MB/s

Thus I should have get 200MiB used in df -h. Hmmm, maybe accurate size 
reporting needs a newer BTRFS than in 2.6.32.3?

Ciao,
-- 
Martin 'Helios' Steigerwald - http://www.Lichtvoll.de
GPG: 03B0 0D6C 0040 0710 4AFA  B82F 991B EAAC A599 84C7

[-- Attachment #2: This is a digitally signed message part. --]
[-- Type: application/pgp-signature, Size: 198 bytes --]