On 07/08/2017 05:26 AM, Veljko wrote:
On Sat, Jul 8, 2017 at 12:52 AM, Stan Hoeppner <stan@xxxxxxxxxxxxxxxxx> wrote:
On 07/07/2017 03:26 PM, Veljko wrote:
I just noticed that I replied to Wol insted to list.
On Wed, Jul 5, 2017 at 8:07 PM, Wols Lists <antlists@xxxxxxxxxxxxxxx>
wrote:
On 05/07/17 17:42, Roman Mamedov wrote:
On Wed, 5 Jul 2017 17:34:09 +0200
Veljko <veljko3@xxxxxxxxx> 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
Thanks for your input, Roman and Wol.
Expanding existing RAID is one of the options, but I was advised by
Stan Hoeppner to do it this way and I tend to believe him on this
subject. With my metadata heavy backup workload, this will provide
better performance.
So my question is still, how can an existing array be added to linear
device, and it's file system expanded over the second array.
For this to work the existing RAID10 array must already be a member of a
linear device with one component device. If this linear array already
exists then you could add another RAID10 array to the linear device. If you
currently have an XFS filesystem sitting atop a 'bare' RAID10 then I don't
believe the linear option will work for you. Thus I'd tend to agree with
others that reshaping your current RAID10 is the best option.
My apologies if I wasn't clear in my previous advice.
Stan
Here is your previous advice:
"Do not use LVM. Directly format the RAID10 device using the mkfs.xfs
defaults. mkfs.xfs will read the md configuration and automatically
align the filesystem to the stripe width.
When the filesystem reaches 85% capacity, add 4 more drives and create
another RAID10 array. At that point we'll teach you how to create a
linear device of the two arrays and grow XFS across the 2nd array."
From this I concluded that it is possible to create linear device
using existing array, but since it is not the case, I'll just have to
create new array, move data to it, than add first array to a new
linear device (1 member), copy my data to it, and than join second
device to it. I wanted to avoid all this copying but will have to do
it. Than I will add one drive to spare-group both arrays will be a
members of, as advised by Andreas. Does this sound OK?
Yes. Although, I was hoping Neil Brown would chime in here. I'm not
entirely sure that you can't do this the way I originally mentioned.
Regards,
Veljko
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