Edson wrote:
I use this kind of clustering, but there is a performance penalty. Not so high, but...
Right, but most importantly it scales. If you observe performance degradation, you can just add another host without needing to touch the other instances. You just have to add the new instance to DNS-SRV or to a load-balancer.
If performance becomes an issue in a t_replicate environment, adding another host doesn't help you much, because each registration has to be handled at every single host of the cluster. And registrations are typically the most frequent requests in a system.
That's just beside the fact that if one host goes down, you will always get an inconsistent usrloc cache among the hosts, because if the host comes up again, you have to mysql-dump the location table from another host and start the proxy. Between the moment of the dump and the moment the proxy finishes reading the location table into the cache, you will miss all registrations. This becomes a problem if you have a large number of actively registering subscribers.
These two issues are the main reasons why I'm very happy with a cache-less solution.
Andy _______________________________________________ Users mailing list [email protected] http://openser.org/cgi-bin/mailman/listinfo/users
