converting one-disk btrfs into RAID-1?

converting one-disk btrfs into RAID-1?

[Tomasz Chmielewski]

Some Linux distributions started adding btrfs support in their 
installers. Unfortunately, you can't specify your own mkfs.btrfs 
parameters, so the best an installer can produce is a btrfs filesystem 
made on one partition.

Is it possible to turn a 1-disk (partition) btrfs filesystem into RAID-1?

Suppose you have your / btrfs filesystem on /dev/vda3, and there is a 
free /dev/vdb3 partition which you would like to use to have btrfs 
RAID-1 - what are the options to set it up like this?


A command like:

	btrfs device add /dev/vdb3 /

will, I suppose, simply make RAID-0 and double your available storage - 
are there any options to make it RAID-1?

Or, will it be RAID-1 after I do:

	btrfs filesystem balance /

?

-- 
Tomasz Chmielewski
http://wpkg.org

Re: converting one-disk btrfs into RAID-1?

[Chris Ball]

Hi,

   > Is it possible to turn a 1-disk (partition) btrfs filesystem into
   > RAID-1?

Not yet, but I'm pretty sure it's on the roadmap.

- Chris.
-- 
Chris Ball   <cjb@laptop.org>
One Laptop Per Child

Re: converting one-disk btrfs into RAID-1?

[David Brown]

On 11/10/2010 19:06, Chris Ball wrote:
> Hi,
>
>     >  Is it possible to turn a 1-disk (partition) btrfs filesystem into
>     >  RAID-1?
>
> Not yet, but I'm pretty sure it's on the roadmap.
>
> - Chris.

Is it possible to view the raid levels of data and meta data for an 
existing btrfs filesystem?  It's easy to pick them when creating the 
system, but I couldn't find any way to view them afterwards.

Re: converting one-disk btrfs into RAID-1?

[Tomasz Torcz]

On Tue, Oct 12, 2010 at 11:32:07AM +0200, David Brown wrote:
> On 11/10/2010 19:06, Chris Ball wrote:
> >Hi,
> >
> >    >  Is it possible to turn a 1-disk (partition) btrfs filesystem into
> >    >  RAID-1?
> >
> >Not yet, but I'm pretty sure it's on the roadmap.
> >
> >- Chris.
> 
> Is it possible to view the raid levels of data and meta data for an
> existing btrfs filesystem?  It's easy to pick them when creating the
> system, but I couldn't find any way to view them afterwards.

  "btrfs f df" will show them, except for few kernel releases when the ioctl()
was broken.

-- 
Tomasz Torcz                                                       72->|   80->|
xmpp: zdzichubg@chrome.pl                                          72->|   80->|

Re: converting one-disk btrfs into RAID-1?

[Hugo Mills]

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On Tue, Oct 12, 2010 at 11:34:31AM +0200, Tomasz Torcz wrote:
> On Tue, Oct 12, 2010 at 11:32:07AM +0200, David Brown wrote:
> > Is it possible to view the raid levels of data and meta data for an
> > existing btrfs filesystem?  It's easy to pick them when creating the
> > system, but I couldn't find any way to view them afterwards.
> 
>   "btrfs f df" will show them, except for few kernel releases when the ioctl()
> was broken.

   Umm...

hrm@vlad:~ $ sudo btrfs fi df /mnt/
[sudo] password for hrm: 
Data: total=303.01GB, used=302.16GB
Metadata: total=3.01GB, used=476.77MB
System: total=11.88MB, used=36.00KB

   This is the latest btrfs git kernel and tools. What should I be
seeing here?

   Hugo.

-- 
=== Hugo Mills: hugo@... carfax.org.uk | darksatanic.net | lug.org.uk ===
  PGP key: 515C238D from wwwkeys.eu.pgp.net or http://www.carfax.org.uk
               --- emacs: Emacs Makes A Computer Slow. ---               

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Re: converting one-disk btrfs into RAID-1?

[Tomasz Torcz]

On Tue, Oct 12, 2010 at 10:49:35AM +0100, Hugo Mills wrote:
> On Tue, Oct 12, 2010 at 11:34:31AM +0200, Tomasz Torcz wrote:
> > On Tue, Oct 12, 2010 at 11:32:07AM +0200, David Brown wrote:
> > > Is it possible to view the raid levels of data and meta data for an
> > > existing btrfs filesystem?  It's easy to pick them when creating the
> > > system, but I couldn't find any way to view them afterwards.
> > 
> >   "btrfs f df" will show them, except for few kernel releases when the ioctl()
> > was broken.
> 
>    Umm...
> 
> hrm@vlad:~ $ sudo btrfs fi df /mnt/
> [sudo] password for hrm: 
> Data: total=303.01GB, used=302.16GB
> Metadata: total=3.01GB, used=476.77MB
> System: total=11.88MB, used=36.00KB
> 
>    This is the latest btrfs git kernel and tools. What should I be
> seeing here?

 Do you have this patch applied?
http://www.mail-archive.com/linux-btrfs@vger.kernel.org/msg06239.html

-- 
Tomasz Torcz                                                       72->|   80->|
xmpp: zdzichubg@chrome.pl                                          72->|   80->|

Re: converting one-disk btrfs into RAID-1?

[David Brown]

On 12/10/2010 11:34, Tomasz Torcz wrote:
> On Tue, Oct 12, 2010 at 11:32:07AM +0200, David Brown wrote:
>> On 11/10/2010 19:06, Chris Ball wrote:
>>> Hi,
>>>
>>>     >   Is it possible to turn a 1-disk (partition) btrfs filesystem into
>>>     >   RAID-1?
>>>
>>> Not yet, but I'm pretty sure it's on the roadmap.
>>>
>>> - Chris.
>>
>> Is it possible to view the raid levels of data and meta data for an
>> existing btrfs filesystem?  It's easy to pick them when creating the
>> system, but I couldn't find any way to view them afterwards.
>
>    "btrfs f df" will show them, except for few kernel releases when the ioctl()
> was broken.
>

I guess it's time to update my System Rescue CD to a version with the 
btrfs command rather than just btrfsctl etc.  Thanks!