Re: Microsoft .NET frontending IBM i

On 10/11/2010 1:31 PM, Thorbjoern Ravn Andersen wrote:

You can get a lot of commodity hardware for that amount of money for
horizontal scaling....

This conversation is just as scintillating as it has been the 724 other times we've had it, and just as theoretical. I say theoretical because I suspect that nobody here is actually running an entire enterprise on several dozen sub-$10K servers.

And because it's theoretical, the horizontal folks miss the crucial bit every time: how in the heck do you horizontally scale an enterprise application? With commodity systems you're not going to mirror the entire application suite on every server. So, how do you figure out which servers run which applications? How do you upgrade them? How do you fail over? How do you distribute modifications?

It's EASY to scale a single application horizontally. A bunch of machines knotted up to serve the database, and then the same application on every user-facing machine. It's not a pretty architecture, but it's functional. It's much harder to do it with a heterogeneous suite, especially if you mix 3rd party and custom code (God forbid you throw open source into the mix). And it's damned near impossible to provide seamless 24/7 redundancy and hot swap with dozens of servers each running bits of the corporation. I'm not saying it can't be done, just that it's not as simple as buying another machine from CompUSA and flipping the switch.

Yes, with an i you have a single point of failure. But you also have a single point of distribution, access and delivery. You HA to another machine for failover and you're done.

Oof... took me ten minutes to write this. That's ten minutes of my life I'll never get back...

Joe