After analyzing the use of the current environment, you are able to involve business sponsors/users in guided discussions for the estimates for the new system. Usually, you build the model for the new environment based on the current environment usage. There are many criteria you can use to build this model.
Note: When building estimates for the new environment, you need to take future growth into consideration. One common consideration is to extrapolate for a 3 years period; thus, you will put the estimate for 3 years in the future. We generally set it this way so that we can have 3 years of operation without need for servers scale up/scale out. Based on customer’s need you might decide to build the estimate for more years as 5 years.
Following are the main extrapolations you will need to make:
1. What is the expected number of users for the new environment?
If this is an intranet portal that includes all company employees, then you could estimate the current number of employees and add to it based on the 3 year growth expectation. Otherwise, you can use the current value from the previous analysis and estimate the growth for the next period.
2. What is the expected peak RPS (Requests per Second)?
Without prior knowledge of the current environment it is hard to build an estimate for the RPS. However, it is relatively easy to extrapolate it from the results received earlier with the LogParser exercise. One option is to assume that the requests will be the same or will grow by a percentage. An option is to assume that the requests will double for the new environment.
Note that you will need to build RPS for the different service applications that we will have in the new environment. It’ll be convenient to have this breakup from the current system; otherwise, you can estimate it by breaking up the RPS from the full system to its difference components.
3. What is the expected Data Size?
There are formulas to estimate the data sizes for the SharePoint content databases; however, a clearer estimate can be done if sizes of current content databases are present.
Note: Based on your comfort with the values estimated above, you might decide to add 10% or 20% as safety margins.
In addition to the items above, you can get more information regarding SharePoint usage in the current environment to use in building the architecture of the new farm. One such important value is the number of items in the search index. This value has a profound impact on the design of the search architecture as we will see later, so having a basis for its estimate helps a lot when architecture is being built.
After building the estimates for the new environment, you should use them to fill the workload tables presented earlier.
This will be the end of the modeling step in the capacity management cycle.
The next step is to start on the design of the new environment. This will be handled in the next article.