Tech Dogg's Dox Tox
Posted in Work at 10:24:17 AM on 25 September 2008 | Comments: 0
Support for RAC on zones has just today been announced for Solaris Cluster Express (SCX) 9/08. You can learn more about this new support by going to the Solaris Cluster Express area on the OpenSolaris web site.
The RAC on zones feature introduces some new, and changes some very fundamental, Sun Cluster concepts, and sets in motion some very big changes in the way you might have thought of Sun Cluster.
Here are the concepts about which you'll likely be hearing more in the future.
In Sun Cluster that's running on the Solaris 9 OS, a node is defined as a physical machine that contributes to cluster membership and is not a quorum device. In this environment, a cluster is a collection of one or more nodes that belong exclusively to that collection.
In Sun Cluster that's running on the Solaris 10 OS, however, these concepts change. A node is now a zone that is associated with a cluster. A voting node is a zone that contributes votes to the total number of quorum votes, that is, membership votes in a cluster. This total determines whether the cluster has sufficient votes to continue operating. And, a non-voting node is a zone that does *not* contribute to the total number of quorum votes, that is, membership votes in a cluster.
In this environment, a cluster is a collection of one or more nodes (that is, zones) that belong exclusively to that collection. A global cluster (a new term for an old concept) and zone cluster (a new concept) are types of clusters.
A global cluster is a type of cluster that is composed only of one or more global-cluster voting nodes and optionally, zero or more global-cluster non-voting nodes.
Note: A global cluster can optionally also include solaris8, solaris9, lx (linux), or native brand, non-global zones that are not nodes, but high availability containers (as resources).
A global-cluster voting node is a native brand, global zone in a global cluster that contributes votes to the total number of quorum votes, that is, membership votes in the cluster. This total determines whether the cluster has sufficient votes to continue operating.
A global-cluster non-voting node is a native brand, non-global zone in a global cluster that does not contribute votes to the total number of quorum votes, that is, membership votes in the cluster.
A zone cluster, which is a new concept, is a type of cluster that is composed only of one or more cluster brand, voting nodes. A zone cluster depends on, and therefore requires, a global cluster. A global cluster does not contain a zone cluster. You cannot configure a zone cluster without a global cluster. A zone cluster has, at most, one zone cluster node on a machine.
Note: A zone-cluster node continues to operate only as long as the global-cluster voting node on the same machine continues to operate. If a global-cluster voting node on a machine fails, all zone-cluster nodes on that machine fail as well.
As you can see, this new feature turns Sun Cluster concepts on their head. You'll hear more about these changes in the coming months.
The clzonecluster man page (PDF) tells you more about the command that you use to manage zone clusters.
As always, let me know what you think.
