Capacity Planning in Change Management

[ecadre]

Hi,

When we need to introduce a new application to our production system, we need to perform a capacity planning.

During capacity planning we usually use a capacity model. There are 3 models :
1. Simulation
2. Analytical
3. Estimation

However could someone please give information about:
For simulation, does it mean that we need to provide a second server with the same type and configuration? Then have peoples try to test that server?

For analytical modelling, I'm a bit confuse of how the software work, I mean how it create a baseline? and how they determine that new application will give xxx percentage of increasing load?

Thanks in advance for your help


Alan

[Diarmid]

Yes simulation means running the workloads on the proposed or very similar configurations, although you can scale down if you don't mind the additional risk.

The last time I had involvement with modelling software it was built round something called multi-class queuing theory and had been developed in conjunction with some serious academic research.

To create a baseline you feed it data about the behaviour of all the servers, networks and other infrastructure involved, data about the placement of file systems, data about human involvement, and data about the workloads (numbers of records, transactions of each kind and the rest. For current systems you can acquire that data using measurement tools against the activities of the servers etc. For new and changed systems you use projections initially, then information from various levels of system tests and full trials and finally you baseline on the real workload after it has been run in.

BMC and Metron are specialists in this area and their information will be way more up-to-date than mine. They both commissioned academic work in this field some time ago (well, technically, in the case of BMC it was the original capacity management specialist company that did this before they were swallowed up as part of a grand acquisition campaign a while back.
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