This blog is the third in a sequence of blogs. It starts with
Licensing, Sizing and Architecting BW on HANA and moves onto
10 Golden Rules for SAP HANA Project Managers. In this piece, I'm going to discuss some tips for making a migration a success from a technical perspective.
1) Create benchmarks
Always benchmark before and af ter. Make sure they are business-relevant, and are run in a place that excludes network and PC problems - the same place each time. Get the query variants and teach the technical team how to run and time the queries. Create an Excel workbook which has queries on the rows and query runs on the columns and run it every day after the migration. Now you can track project success.
2) Exclude unnecessary risks
I've seen so many projects that include unnecessary risks. Here are some examples
- Not doing full backups that allow proper restore points
- Putting installation files on network shares
- Having application servers on different networks to database servers
Find ways to remove these risks, you don't need them in your project.
3) Get your landscape in sync
Your landscape needs to be synchronized. Check your BW versions are part of a proper Support Package Stack and they aren't on wrong revisions.
On the HANA side, make sure you are on the latest revision of HANA. Yes, that means database
and client
and DBSL. A landscape that is not in sync is a landscape which is likely to fail.
4) Run an independent check of your HANA system
Unfortunately, hardware vendors sometimes mess up HANA installation and configuration. SAP have Note 1943937 which has details and ther e is an IBM-specific tool which checks for GPFS issues too.
Whilst you're there, check the trace folder of your HANA system. If it has a lot of logs, crashes or dumps then you have a problem. Get someone to resolve it before continuing.
5) Get the latest table sizing and table redistribution notes
There are SAP notes that apply fixes for table sizing and redistribution and these need applying prior to the export process. Search for the latest version and then implement them before exporting.
Specifically, check SAP Note 1921023 for SMIGR_CREATE_DDL and 1908075 for Landscape Redistribution. Also make sure you download the latest row store list from SAP Note 1659383 .
6) Get everything completely up to date
This is the #1 reason why I see problems in HANA migrations. You have to get everything up to date, especially SWPM, kernel, disp+work and r3load software. It requires manual work and you have to repackage the SWPM kernel files at times so you get the latest version. If you skip this or cut corners, you will pay for it later in the upgrade project.
7) Include the latest patches and notes
There is a common wisdom on SAP projects where people go to patch level N-1. This isn't the case with HANA, and you need to make sure you are on the latest patch during your project lifecycle. In addition, you need to search OSS for notes which need applying. One useful tip here is to use the SAP Note Search "Restrict by Product Components" --> SAP_BW --> Release 740 to 740 -> SAPKW74005 (for BW 7.40 SP05). You will now only see notes that relate to BW 7.40 SP05, which is neat.
Make sure you check SAP Note 1908075.
It's well worth spending time doing this analysis when you have some spare moments and noting the SAP Notes that you need to apply after the migration. If you don't do this then you will need to do it when you are tired, immediately after the migraiton.
8) Check the Important Notes list
The master note for BW 7.4 is SAP Note 1949273 and for BW 7.3.1 it is 1846493. You need to check and apply the corrections (and connected corrections) in these notes.
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