Re: Linear device of two arrays

[Wols Lists <antlists@youngman.org.uk>]

On 05/07/17 17:42, Roman Mamedov wrote:
> On Wed, 5 Jul 2017 17:34:09 +0200
> Veljko <veljko3@gmail.com> wrote:
> 
>> Hello,
>>
>> I have a RAID10 device which I have formated using the mkfs.xfs
>> defaults (Stan helped me with this few years back). I reached 88%
>> capacity and it is time to expand it. I bought 4 more drives to create
>> another RIAD10 array. I would like to create linear device out of
>> those two and grow XFS across the 2nd device. How can this be done
>> without loosing the existing device's data? I would also like to add a
>> spare HDD. Do I have to have a separate spare HDD for each array or
>> one can be used by both of them?
> 
> Why make another RAID10? With modern versions of mdadm and kernel you should
> be able to simply reshape the current RAID10 to increase the number of
> devices used from 4 to 8.
> 
> 
I was thinking of replying, but isn't that not possible for some
versions of RAID-10?

My feeling was, if you can't just add drives to the existing raid 10,
create a new one which you can expand, migrate the fs across (btrfs
would let you do that live, I believe, so xfs probably can too), then
you can scrap the old raid-10 and add the drives into the new one.

Cheers,
Wol