RE: CEPH & Shared RBD Volumes

RE: CEPH & Shared RBD Volumes

[Cook, Nigel]

Folks,

Can CEPH support 2 clients simultaneously accessing a single volume - for example a database cluster - and honor read and write order of blocks across the multiple clients?

Regards,
Nigel Cook
Intel Fellow & Cloud Chief Architect 
Cloud Platforms Group
Intel Corporation
+1 720 319 7508

Re: CEPH & Shared RBD Volumes

[Smart Weblications GmbH - Florian Wiessner]

Hi Nigel,

Am 08.12.2014 15:30, schrieb Cook, Nigel:
> Folks,
> 
> Can CEPH support 2 clients simultaneously accessing a single volume - for example a database cluster - and honor read and write order of blocks across the multiple clients?
> 

Yes, we use ocfs2 ontop of rbd, gfs2 should also work...

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Re: CEPH & Shared RBD Volumes

[Sage Weil]

On Mon, 8 Dec 2014, Smart Weblications GmbH - Florian Wiessner wrote:
> Hi Nigel,
> 
> Am 08.12.2014 15:30, schrieb Cook, Nigel:
> > Folks,
> > 
> > Can CEPH support 2 clients simultaneously accessing a single volume - for example a database cluster - and honor read and write order of blocks across the multiple clients?
> > 
> 
> Yes, we use ocfs2 ontop of rbd, gfs2 should also work...

You do need to disable client-side rbd caching, though (on librbd).  The 
librbd cache is crash-safe but not coherent across clients, and clustered 
file systems expect coherency (caches in a SAN are at the disk or shared 
controller, not the client).

sage