Well, that depends. Suppose the application is a webserver. Not your
simple static page web server, that one is on a shared nothing cluster
already. It's a webserver that has a big honkin' database, with lots
of data being updated all time, the classic sort of thing that a big
SMP can handle but a cluster could not. Fair enough?
Now imagine that the system is a collection of little OS images, each
with their own file system, etc. Except /home/httpd is mounted on
a globally shared file system. Each os image has its own set of
interfaces, one or more, and its own http server. Which updates
data in /home/httpd.
Can you see that this is a non-issue? For this application, the ccCluster
model works great. The data is all in a shared file system, nice and
coherent, the apps don't actually know there is another OS banging on the
data, it all just works.
Wait, I'll admit this means that the apps have to be thread safe, but that's
true for the traditional SMP as well.
----- Larry McVoy lm at bitmover.com http://www.bitmover.com/lm - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/