combining 2 RAID 10 pools to one filesystem

combining 2 RAID 10 pools to one filesystem

[Gal Buki]

Hi

I have RAID 10 using 4 times 500GB drives (1TB of storage).
Is it possible to create another RAID 10 with 4 times 250GB drives 
(500GB of storage) and then combine those two RAIDs to one file system 
so that I would be able to get 1.5TB?

If I create one RAID 10 with all 8 drives I would only be able to use 8 
times 250GB /2 = 1TB, right?

Thanks,
Gal

Re: combining 2 RAID 10 pools to one filesystem

[Chester]

I'm sure this is possible if you use /dev/md's, but doesn't this
basically make the redundancy of the raid10 useless?

On Wed, Feb 16, 2011 at 8:50 PM, Gal Buki <buki@torus.ch> wrote:
> Hi
>
> I have RAID 10 using 4 times 500GB drives (1TB of storage).
> Is it possible to create another RAID 10 with 4 times 250GB drives (5=
00GB of
> storage) and then combine those two RAIDs to one file system so that =
I would
> be able to get 1.5TB?
>
> If I create one RAID 10 with all 8 drives I would only be able to use=
 8
> times 250GB /2 =3D 1TB, right?
>
> Thanks,
> Gal
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Re: combining 2 RAID 10 pools to one filesystem

[Hugo Mills]

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On Wed, Feb 16, 2011 at 10:50:57PM +0200, Gal Buki wrote:
> I have RAID 10 using 4 times 500GB drives (1TB of storage).
> Is it possible to create another RAID 10 with 4 times 250GB drives
> (500GB of storage) and then combine those two RAIDs to one file
> system so that I would be able to get 1.5TB?
> 
> If I create one RAID 10 with all 8 drives I would only be able to
> use 8 times 250GB /2 = 1TB, right?

   No, just add the new drives to the existing btrfs pool, and run a
balance, and you should get a btrfs filesystem with 1.5TB of
mirrored/striped storage.

   Hugo.

-- 
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