In Praise of Mainframes

I've had a number of discussions recently regarding the sizing of servers for use in virtualization initiatives.  On one hand, keeping the cpu count low has the advantage of keeping software costs down, and allows an infrastructure to be constructed of low-cost, commoditized servers.  On the other hand, using larger servers has an advantage in that it provides better economies of scale when combining workloads, and also provides higher headroom for peak demands.  This has understandably been a hot topic of late.

When I try to put this in perspective I can't help but turn my thoughts to the mainframe world, where virtualization and proper capacity planning have been mainstays for decades.  This is the epitome of the scale up model, and few if any mainframe environments are suffering from the sprawl and underutilization that we are seeing in the opens systems world.

And there is, in my opinion, a significant underlying reason for this. It is what I call reverence for the platform, and, put simply, it is the fact that people respect big, expensive systems more than small, cheap ones. Why do we rarely see VM sprawl on mainframes? Because people don't mess with them.

This respect is important.  How important? Just watch any movie.

Nobody goes on a quest to seek advice from "blade rack"

Nobody tries to defeat the enemy by knocking out their "midrange"

Nobody crawls through air ducts to gain access to "file and print"

They go to Mainframe

They go to the biggest, most vertically scaled thing they can find.

In fact, the only prominent example of a horizontally scaled technology in a movie that I can think of is the Borg. But it was evil – more like a grid with attitude. And that may have been a TV show.

So next time you are sizing servers for virtualization be sure to pay some attention to the ultimate non-technical consideration: reverence for the platform.  And who knows - if a bunch of actors come walking through the server room they may just try wreck your stuff instead…

Comments

[Iroc]

I work on Both an AS400 and a networked PC Virtual Mainframe.

Here's my take;
Would you rather pull a cart with a Donkey that calls home if it goes lame yet continues to limp along?
Or
Would you rather pull that cart with 100 chickens that if one gets sick 99 stop to look at it?

Somebody hitch up Eeyore I want to deliver these chicken dinners.

[Andrew Hillier]

A recent discussion around VM sprawl reminded me of your comment. We are seeing virtual environments where the number of VMs created is not at all what was originally envisioned, and the number of "deadwood" VMs that are turned off but not deleted is growing. There is clearly hesitation in deleting an inactive machine when nobody knows who created or why it exists.

To extend your analogy to the virtual world, this makes it more like 100 chickens pulling a cart that is already full of dead chickens. And they are probably connected to the cart with fibrechannel...