Least impacting way to estimate decompressed size of ADABAS/Natural database.

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I’m an analyst with limited Mainframe experience, part of a team that is migrating data from ADABAS/Natural into a SQL Server data warehouse. I need to estimate the size of my ADABAS/Natural database so that we know how large the SQL Server’s storage would need to be.

My main challenge so far is access to resources, we have limited availability of Natural programmers and DBA’s as they are fully preoccupied with maintaining current operations. So I need to find a way to do this that is minimally impacting. My preferred method would be to utilize one of the reports we can easily obtain, which are:
- PREDICT Data Dictionary &
- ADAREP Report
[Note: I’m able to request other reports, but again only if the generation of those reports is minimally invasive]

My secondary problem is, so far I can only find information on the sizing of the data in it’s compressed form - and I understand that ADABAS has excellent compression and that wouldn’t be an accurate way to estimate size for a SQL Server. So I am hoping there is a way to estimate the decompressed size of the ADABAS/Natural database using the compressed sizing (hopefully in conjunction with some other data that explains the compression process?). If not, what’s the best way to find a relatively accurate estimate of the size of an ADABAS/Natural database?

I hope you can help me, or at least lead me in the right direction.

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Predict will list all the fields in a record/file. Add the field lengths to determine the record length. Multiply by the record count from an ADAREP to get the file size.

Remember that D-format fields are 4 bytes, T-format 7 bytes, L-format 1 byte, Control Variables 2 bytes. Check for Unicode or DBCS usage, as these would affect alpha field lengths.

For multiple-value fields (MUs and PEs) you will need some “maximum count” from the application’s technical design documents to use as a multiplier for each MU and PE component.

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Thanks for the help Ralph, that seems do-able. I’ll pass on the message to my team.