Great question because sizing is art as well as science. In my experience I have found that addressing the largest lists and modules are what will get you closest to the actual size. Here's a template I use below. Oh, and remember... estimate the size of the lists as well as the modules. You'd be surprised how much space lists take. Each list item takes 500 Bytes as overhead + the length of the text! Key point: Don't over analyze. As you can see below the P7 SKU List and any associated module will determine the size of this module. So focus on the biggest lists and the respective modules that use them.
Hi Louise, hope you're doing fine. Do you mind sharing the template for calculation. I'm having some discrepancies regarding the actual model size (59 GB) vs. using the approach of 1,000,000,000 = 9.3 GB, the model has 8.5 billion cells that value the size at 78 GB.
First of all we are not from Anaplan, so our vetting it doesn't mean Anaplan doing it 🙂
To me I believe it is extremely tough to calculate the model size in the design phase. There are so many nuances to it - Dimensions including Native Time, Native Versions, Switchover, Formats of line items, number of list items etc. However we can still give a ball park figure to the clients based on the experience from prior implementations and little bit of calculations based of the above information provided.
I am not sure if item of Native Time or Native Version takes 500 bytes of space as well - highly unlikely. If that was the case then without using Time as a dimension in the module we could see model size going up based on the number of time periods that we have set in the backend, which is not the case - atleast I have not seen that.
Also Number of Text Characters in any Text Formatted line item also drives the model size but you won't see it in the front end. Your may see model being 50 GB in the front end but in the backend it may be more than 500 GB due to excessive usage of Text formatted lines in the model - this reduces the performance but it doesn't add up to your calculations.
Switchover is another area where it gets tricky - any switchover cell doesn't add up to the total size.