By Alan Swahn
Are Random Processes Really Random?
Today’s blog is really a thought exercise on random processes. Do random selections always yield random results? Let’s run a test.
Let’s say that we have a Cloud compute grid where the servers are mapped to a 0-1000 by 0-1000 grid. Furthermore, we are using XWare virtualization technology and xMotion to move workloads around the compute grid randomly. Each time a workload moves, the direction is randomly selected from (N, S, E, W, NW, NE, SW, or SE) and the color assigned to each. When the workload lands on the next server, the server is color coded. The distance traveled is always 2/3 from where it is to the edge of the grid, where the edge of the grid is determined by the random direction.
In the example below, the workload starts at randomly selected X and moves South (direction selected at random), lands on a server, which is colored purple. The next direction selected at random is Northeast and the server where the workload lands is colored blue. The next random move is Southeast and the server is colored green.
This compute grid is really big—1001 by 1001 computers or 1,002,001 computers. To see if the resulting workload moves result in a random pattern or not, this process was repeated 1 billion times, with the picture (a fractal) below being generated. We see that a seemly random process can lead to a very deterministic result. Interestingly, only 62% of the servers were touched by this workload.
In an IBM audit situation, if you could convince IBM that you should only pay for 62% of the servers in the cluster, because you can prove that xMotion will only move the workload to this percentage of servers, you would still lose the argument, since XWare isn’t an IBM Eligible Virtualization Technology!
Even if it were an approved virtualization technology, you’re probably still on the hook to license for all the servers in the cluster if you have “full capacity” licenses (depending on the license model in use). If you have “sub-capacity” licenses then you’d have to license for the Virtualization Capacity of the group of servers. Virtualization capacity is “the sum of the virtual core capacity available to a product.”
OK, so I managed to get a little bit in there on license management.
To learn more about how to simulate changes to your IT environment to understand the impact on your license position, please visit our website to read about ‘What If’ analysis.