You can go with 512 emulation and later you can recreate the brick without that emulation (if there are benefits of doing so).
After all, you gluster is either replica 2 arbiter 1 or a replica 3 volume.

Best Regards,
Strahil Nikolov

On Oct 1, 2019 09:26, Satheesaran Sundaramoorthi <sasundar@redhat.com> wrote:
On Tue, Oct 1, 2019 at 11:27 AM Guillaume Pavese <guillaume.pavese@interactiv-group.com> wrote:
Hi all,

Sorry for asking again :/

Is there any consensus on not using --emulate512 anymore while creating VDO volumes on Gluster?
Since this parameter can not be changed once the volume is created and we are nearing production setup. I would really like to have an official advice on this.

Best,

Guillaume Pavese
Ingénieur Système et Réseau
Interactiv-Group

Hello Guillaume Pavese,
If you are not using --emulate512 for VDO volume, then VDO volume will be created
as 4K Native volume (with 4K block size).

There are couple of things that bothers here:
1. 4K Native device support requires fixes at QEMU that will be part of
CentOS 7.7.2 ( not yet available )
2. 4K Native support with VDO volumes on Gluster is not yet validated
thoroughly.

Based on the above items, it would be better you have emulate512=on or delay
your production setup ( if possible, till above both items are addressed )
to make use of 4K VDO volume.

@Sahina Bose Do you have any other suggestions ?

-- Satheesaran S (sas)

On Fri, Sep 27, 2019 at 3:19 PM Sandro Bonazzola <sbonazzo@redhat.com> wrote: