Hi, On Fri, Aug 29, 2008 at 3:37 PM, AdamR <[EMAIL PROTECTED]> wrote: > According to the Jackrabbit wiki, all cluster nodes must store their data in > the same globally accessible location. So, from a Jackrabbit point of view > there is still a single point of failure and availability is not improved. > Obviously this single persistant store can be clustered itself to meet > availablity requirements - but what value does clustering at the Jackrabbit > level add?
The main benefit from the current clustering feature in Jackrabbit is that you *can* access a single clustered backend store from multiple Jackrabbit instances. Before clustering support was added, you could not run two Jackrabbit servers pointed to the same backend store. Also, the clustering feature makes sure that all caches and search indexes remain coherent, that metadata changes like node type and namespace registrations are automatically propagated across the cluster, and that observation works correctly even when changes are committed by other cluster nodes. That said, you are right in that the current clustering feature is somewhat incomplete in that it depends on external clustering solutions. See the dev@ mailing list for some discussions about potential new Jackrabbit persistence architectures that would feature built-in clustering. BR, Jukka Zitting
