Okay you ask, why did I name my blog after a German phrase and what does it mean? If you translate the phrase “Kleinvieh macht auch Mist” to English, it means “even small animals create some ****”. My TechEd session is named “Replatforming SAP Systems to Virtual Environments” and will describe my company’s logic, trials, and tribulations of moving over 60 small, medium and large sized UNIX servers into 4 large ones. The major point is that in my opinion it is easier (and better) to manage a few large servers than many small ones. In fact, you can make a case that fewer hardware resources are required when you move to large, consolidated servers. Seymore Cray was quoted as saying “if you have to plow a field, which would you rather use? Two strong oxen or 1024 chickens“. I really subscribe to the “two strong oxen” method and have based my TechEd session on this approach.
Here is an example, suppose you have a requirement for 5 different SAP solutions and each solution requires 16 CPU cores to satisfy its peak usage period. Using the “small animal” approach, you would have 5 separate (physical) servers, each with 16 CPU cores. Now, suppose that 90% of the time, the average usage of each server is only 50% (or 8 CPU cores). The end result of the solution would be 5 servers and 80 CPU cores.
Now, as an alternative, consider satisfying this requirement with one large server that can share CPU cores between applications as needed. Since we know that on average, each application requires 8 CPU cores, we can size the large server with 5 virtual systems, each with 8 CPU cores. We can then add an additional 16 cores to this large system and make them float between virtual systems as needed. The end result is a requirement for only 56 cores. On top of this, if one virtual server really needs it, it could borrow up to 16 floating cores and any of the unused cores from the other virtual systems.
We have used this logic to replatform our entire SAP portfolio and really feel that we gained a lot in performance, manageability, and reliability as a result of it. Come to my TechEd session in Phoenix on Tuesday, October 13 (11:15AM) to get all of the gory details!
Thanks for reading!