The idea of regions and zones is to replicate Amazon's S3 storage. Here's some links from Amazon descriping EC2 regions and zones (http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/using-regions-availability-zones.html) and S3 Regions (http://docs.aws.amazon.com/AmazonS3/latest/dev/LocationSelection.html). The S3 links are more appropriate, but you need some the EC2 background.
Clusters are (usually) a single group of servers in a single location. This doesn't have to be the case, but people generally don't mix multi-location clusters and federation. Regions and Zones are how ever you want to set them up. You could have a single region called "Earth", or many Regions like Amazon does. Each cluster belongs to a single region, and a region has one or more clusters. Zones are inside regions. Federated replication happens between zones. A cluster can host any number of zones, as long as they all belong to the same region. Only the master zone is writable. You can read from the master or slave. Several common setups are cross replication or ring replication between clusters. In a cross replication setup, cluster1 would have zone1master and zone2slave. cluster2 would have zone1slave and zone2master. In a ring, cluster1 would have zone1master and zone3slave. cluster2 would have zone2master and zone1slave. cluster3 would have zone3master and zone2slave. cross replication is just the 2 cluster version of ring replication. You're welcome to make this replication strategy as complicated as you're willing to deal with. As far as I know, there isn't any published disaster recovery documentation. My understanding is that in the event of a disaster in the master zone, you disable replication and start writing to the slave. When the old master zone comes back online, you delete it, and set it up as a slave of the current master. Once re-replication completes, you could fail back to the old master. I'm not aware that anybody has tested this, but the general idea should work. I'm hoping that it might be possible to skip the delete, but it will involved some extensive testing. I'm not aware that anybody has tested this, much less gotten it to work. I plan to try it and write it up... but I'm not sure when. On Wed, Jun 4, 2014 at 11:15 PM, lijie8...@126.com <lijie8...@126.com> wrote: > hi , I have some question about region and zone > > 1. why define the concepts of "REGION , ZONE", what the purpose is it. > 2. what the relation between region , zone ,cluster , and how design > the federated architecture. and how do the disaster recover. > > > Expect receiving your early reply,thank you . > ________________________________ > lijie8...@126.com > > _______________________________________________ > ceph-users mailing list > ceph-users@lists.ceph.com > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > _______________________________________________ ceph-users mailing list ceph-users@lists.ceph.com http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
