> From: Ben Swartzlander [mailto:b...@swartzlander.org] > Sent: Thursday, August 27, 2015 8:11 PM > To: OpenStack Development Mailing List (not for usage questions) > > On 08/27/2015 10:43 AM, Ivan Kolodyazhny wrote: > > > Hi, > > Looks like we need to be able to set AZ per backend. What do you > think about such option? > > > > I dislike such an option. > > The whole premise behind an AZ is that it's a failure domain. The node > running the cinder services is in exactly one such failure domain. If you > have 2 > backends in 2 different AZs, then the cinder services managing those > backends should be running on nodes that are also in those AZs. If you do it > any other way then you create a situation where a failure in one AZ causes > loss of services in a different AZ, which is exactly what the AZ feature is > trying > to avoid. > > If you do the correct thing and run cinder services on nodes in the AZs that > they're managing then you will never have a problem with the one-AZ-per- > cinder.conf design we have today. > > -Ben
I disagree. You may have failure domains done on a different level, like using Ceph mechanisms for that. In such case you want to provide the user with a single backend regardless of compute AZ partitioning. To address such needs you would need to set multiple AZ per backend to make this achievable. __________________________________________________________________________ OpenStack Development Mailing List (not for usage questions) Unsubscribe: openstack-dev-requ...@lists.openstack.org?subject:unsubscribe http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
