Switch to RBD format 2 by default after Firefly

Switch to RBD format 2 by default after Firefly

[Wido den Hollander]

Hi,

With Ubuntu 14.04 now shipping with the 3.13 kernel it fully supports 
Format 2 in both librbd and krbd.

For RHEL 7 there will be a extra yum repo with a module which supports 
format 2, so isn't it that that after Firefly we change 
'rbd_default_format' to 2?

I still see a lot of images being created with format 1 and that will 
otherwise be hunting us for a long time.

I'd vote for making format 2 the default or at least patch the 'rbd' 
tool to create format 2 images.

-- 
Wido den Hollander
42on B.V.

Phone: +31 (0)20 700 9902
Skype: contact42on

Re: Switch to RBD format 2 by default after Firefly

[Ilya Dryomov]

On Tue, Apr 8, 2014 at 4:47 PM, Wido den Hollander <wido@42on.com> wrote:
> Hi,
>
> With Ubuntu 14.04 now shipping with the 3.13 kernel it fully supports Format
> 2 in both librbd and krbd.
>
> For RHEL 7 there will be a extra yum repo with a module which supports
> format 2, so isn't it that that after Firefly we change 'rbd_default_format'
> to 2?
>
> I still see a lot of images being created with format 1 and that will
> otherwise be hunting us for a long time.
>
> I'd vote for making format 2 the default or at least patch the 'rbd' tool to
> create format 2 images.

Fancy format 2 striping is not supported by krbd.  We've had a couple
people who confused format 2 support with the ability to set their own
stripe settings, so we'll need to be more vocal about it.

Thanks,

                Ilya

Re: Switch to RBD format 2 by default after Firefly

[Wido den Hollander]

On 04/08/2014 02:56 PM, Ilya Dryomov wrote:
> On Tue, Apr 8, 2014 at 4:47 PM, Wido den Hollander <wido@42on.com> wrote:
>> Hi,
>>
>> With Ubuntu 14.04 now shipping with the 3.13 kernel it fully supports Format
>> 2 in both librbd and krbd.
>>
>> For RHEL 7 there will be a extra yum repo with a module which supports
>> format 2, so isn't it that that after Firefly we change 'rbd_default_format'
>> to 2?
>>
>> I still see a lot of images being created with format 1 and that will
>> otherwise be hunting us for a long time.
>>
>> I'd vote for making format 2 the default or at least patch the 'rbd' tool to
>> create format 2 images.
>
> Fancy format 2 striping is not supported by krbd.  We've had a couple
> people who confused format 2 support with the ability to set their own
> stripe settings, so we'll need to be more vocal about it.

Ah, that's something I've missed. Never used that in combination with 
krbd. So yes, we need to be more vocal about that.

Maybe even set a warning in the 'rbd' cli tool? Or at least in the 
help/usage.

>
> Thanks,
>
>                  Ilya
>


-- 
Wido den Hollander
42on B.V.

Phone: +31 (0)20 700 9902
Skype: contact42on