Cognos - How to calculate space requirements 1

[u253458]

I am trying to build a cube on the server and estimating the space required to build the cube on the server. I think, I need to add space for input files + Model file + MDC size + Work files

To calculate size of work files.

I get various formulas, to use those methods, I need to the know the total number of categories, dimensions and measures.

My question is from a given cube or model, how can I get the total number of categories?

Also, does someknow of any quick method of calculating space requirements for work file?

Thanks

 

[lstephane]

Hi,

Do you know how to evaluate the final .MDC file size before creating the model itself ?

Thanks !

Stéphane Lambert, Analyst/Programmer - BI Specialist
Info Quest (IQ), Data Warehouse System
McKesson Canada Corporation

EMail: stephane.lambert@mckesson.ca

 

[flex13]

To get the exact category count from the model, you can generate the categories and look at the log file, or turn on the category count option and add them up yourself.

Rule of thumb for work file size, 3x the amount of data that you have. IF you have 2 GB's of data, allow for 6GB of temp space.

Now, as for predicting the actual cube size, there is no clear cut formula for this. There are MANY factors that influence this including:

- Amount of user classe views
- Alternate hierarchies
- Length of category names
- NUmber of categories
- Number of measures
- Etc

Just one example for length of category names, is the following:

A measure would be stored in the cube based on it's intersection so,

Sales.ProductA.1997Q1.12345.23

IF you used codes instead of names you could shorten the intersection to soemthing like:

Sales.ProdA.1997Q1.12345.23

In this VERY simple example, we have shaved off three characters for this one intersection. In a cube that has MILLIONS of intersection, imagine the sizing impact that the three characters would have.

 

[lstephane]

OK... thanks....

But is there a best pratice to say, by example, caluculating the amount of possible categories and let say multiply by 3 (just an example) and it will give us a good average of the final size of the MDC file ?

Stéphane Lambert, Analyst/Programmer - BI Specialist
Info Quest (IQ), Data Warehouse System
McKesson Canada Corporation

EMail: stephane.lambert@mckesson.ca