On 10 October 2014 19:04, Chris Green cl@isbd.net wrote:
On Fri, Oct 10, 2014 at 06:50:44PM +0100, Ewan Slater wrote:
A lot of in memory data grids use multicast auto discovery, so you can scale the cluster out and back easily, without having to specify what's running where up front.
Does that assume that *everything* on the cluster is part of the sharing? If not then how do they decide who to share with?
In the simplest case yes - the data is available across all the nodes in the cluster. The data will be partitioned (the key for an object is hashed to determine which partition it goes on) and the nodes exchange data about which node has which partition(s). So the amount of data that the cluster can hold increases as you add more nodes.
You may then have clients which can call the cluster, but do not themselves store data.