You're right, the multiple server feature is intended only for clustered instances, and given that GlassFish 3.0 and 3.0.1 do not support clusters, this feature does not officially work yet in GlassFish 3.
Depending on what you want to accomplish before GlassFish 3.1, things might work as you want. Please read on.
What happens at runtime is this. The client-side ORB works through the list of multiple servers you list in sun-acc.xml trying to contact a single server-side ORB (in what it expects to be a cluster). Once connected to one server ORB, the client ORB stops looking at the list of servers in sun-acc.xml and instead learns from the server ORB about all the cluster instances that are up and running. Load balancing and failover then use [i]that[/i] server list. The endpoints you list in sun-acc.xml are used only for that first, bootstrap contact.
If you had two non-clustered instances and listed both in the sun-acc.xml, the client ORB would work down the list attempting to contact one. Once it succeeded, the client ORB would send all requests to that one server. It would not do load balancing or failover.
Hope that helps.
- Tim
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