I personnaly do not recommend anything by lack of knowledge (but Bill Burke may answer on this).
A pure software solution is under development though (but it will still need some basic load balancing though... and DNS is not a really viable solution...)
I have used a hardware product from CoyotePoint that works rather well and is less costly than those mentioned. Only downside so far has been it's handling of sticky sessions for AOL clients, but I believe they are working on a patch.
The linux virtual server is very good, however it too is going to suffer from non-persistence. Persistence can only be guaranteed if the load balancer is using cookies to tag the clients and inspecting headers. LVS tries persistence based on IP, but will crack when AOL and other proxy servers hit it. If you also need SSL, then best bet is to get a commercial loadbalancer that will support SSL cards in the load balancer. If not, then use LVS, but make sure you have session sharing going on in your servlet container and full clustering of jboss...
Can someone point something about this issue, regarding what JBoss 3.x version can do?
I'm quite confused about the clustering topology to use, as the docs focus on the ejb clustering issues, particulary how the "smart stub" work and so on.
I would like some pointers on restrictions and advices about clustering with Jboss as a full product. By "full product" I mean JBoss as the complete JBoss+Servlet+Web server. For instance, is it supose/needed to have a loadbalancer on front of the servers?