Introduction
Sizing implies deciding hardware necessities such as memory, CPU control, disk space, I/O capacity, and network transmission capacity. It is an iterative process to translate business requirements into necessary hardware requirements and is ordinarily performed early within the phase of the project.
To prepare your BW system to upgrade/migrate to HANA, it’s important to estimate the memory size of the new HANA server. The report (/SDF/HANA_BW_SIZING) was made available from BW 7.3 version. This sizing report helps you answer the following requirements:
You are using SAP BW and you:
- Want to migrate your database from any database to SAP HANA (i.e. SAP BW powered by SAP HANA), or you
- Want to convert your SAP BW system into an SAP BW/4HANA system.
You want to run the Sizing Report:
- BEFORE migration, because you need more information about the hardware resources required to migrate onto HANA, or
- AFTER migration, because you want to verify if the sizing is correct.
For any questions or clarifications please first review SAP note 2610534 and 2363248 for reference as it would mostly likely answer all your questions. 🙂
How to access the report:
Go to Tcode SE38 - enter "/SDF/HANA_BW_SIZING" and execute.
General Section
1 - If you want to save output of the results to specified file in the DIR_HOME work directory of application server (i.e. Tcode AL11). Use an appropriate naming conventions when saving the file. (Ideally would be suitable to name is (HANA_SIZING_System ID). the file name should start with "HANA_Sizing".
2 - Depending on resources availability on the system you can choose and specify number of parallel processes to analyze tables. Make sure you have enough free work process or run the report during quiet period of time.
3 - For execution on HANA only (If a table was completely unloaded, then unload it again after analysis).
4 - If you also want to determine the CPU requirements along with the memory requirements of a given BW system then you must comply with SAP note 2502280 to activate analysis for CPU requirement. Under certain conditions, the BW/4HANA sizing report can analyze historical statistics data to derive an estimate of the CPU requirements. By checking this option you confirm that you have read and understood the note and comply with its contents. Please go through the disclaimer section in this SAP note 2502280. Refer to attachment (slide 😎 in this SAP note.
5 - Select this option if you're target system is BW/4HANA release.
Precision Section
By default, the "Low" option is selected. The ‘Low’ precision option should already give a rather comprehensive estimate of the future HANA size. However, it is up to you to decide accordingly. Note: Higher precision results in higher sampling rates and higher runtimes. Usually, low precision delivers sufficient reliable results hence by default this options is selected. Ideally Medium and high options would be more suitable for small systems where you would have low row counts etc.
Scenario / Subset Selection
1 - Select this option enable Scenario / Subset selection functionality. With this you can determine the HANA size for parts of your source system by identifying all top level Infoproviders that needs to be part of your scenario or that you would like to exclude respectively. See more info in SAP note 2296290.
2 - Incase you want to be very specific and only size your target system based on certain tables or Infoproviders then you can use option 2 shown in the above screen shot. Here you can enter list of technical names of top infoproviders which are contained in your scenario. Dependent objects will be added automatically.
3 - Specified scenario can either be used for new BW system or can be added to an already existing one. Alternatively, you can exclude the specified list from sizing calculation. For more context on these 3 given options and understand what they do (refer to attachment (slide 9,10,11) in this SAP note. SAP note 2296290.
Note:
In order to estimate the resource requirements of two BW systems consolidated into one single system, the following procedure could be followed:
- Execute a “normal” sizing of the Main system (usually the largest one) using the BW/4HANA Sizing Report.
- If any other systems also need to be considered and consolidate into the leading system, then you run the BW/4HANA Sizing Report with this option (Select Use system subset only) & (Subset of existing system)
- If necessary, sub-scenarios of the system can be extracted based on sets of InfoProviders (List of Top level InfoProviders).
- You don't need to select this subset option if you are planning to just upgrade an existing BW system (Let's say from BW 7.50 to BW/4HANA). In such case the memory and CPU requirement does not change.
Future Growth:
This section is very helpful In Case you want to consider also the future growth of the system to be part of the sizing estimation. Refer to attachment (slide 13) in this SAP note 2296290.
1 - If you would like the report to consider any future growth calculation as part of the report then this flag needs to be selected.
2 - You can specify the number of years that should be considered as part of the growth. (This depends on you as system admin who would know better what the expected future growth rate would be (i.e. 5%, 10%, 15% etc).
3 - You can choose either in (Percentage %) or (Growth in GB). Choose accordingly. Percentages are more intuitive than absolute growth numbers.
4 - Here you can enter the value of the growth expected. (For example - you might say we expect 10% growth in the system size per year for the next 3 years) If so the report would calculate and provide estimation as to how much HANA size is expected after year 1, year 2 year 3 etc.
Planning Applications
If you want to have BPC planning to be considered then the below options can be used to accommodate the same. For detailed information on this option review Refer to attachment (slide 14) SAP note 2296290.
1 - Select this option if Planing sizing needs to be considered for your scenario.
2 - Use the "Calculate" button to derive sizes from RSDDSTAT statistics.
3 - Add user number for planning scenarios.
4 - Add estimated size per planning scenario.
For the above activity you must read and review SAP note 2367899 BW-IP: Planning events (sizing) first. Depending on the system release the note might already be applied into your system so after that you should run up to 3 scenarios of different size one by one and ensure while you perform that activity there should be no other planning scenarios being executed on the system by any one else.
Note: The calculation of the memory required for a planning sequence is only possible if the planning scenario contains a SAVE event.
Multi Temperature Data
In some of the latest versions of this report you want to consider the DTO concept for your new target system.
1 - If you have any Write-optimized (A-DSO) to be considered as WARM then enter them in this field. Give the technical names of the Infoprovider only. Tables such as PSA and Changelogs automatically gets considered as WARM. These DB tables which contain warm data will have partial contribution to the overall sizing results. Refer to attachment (slide 18) SAP note 2296290.
2 - Incase you have plans to use Extension nodes then you can select the option accordingly for storage of warm (A-DSO's).
Memory Configuration
In this section you choose and specify which node sizes should be considered as part of this execution. Refer to attachment (slide 21) SAP note 2296290.
1 - It depends on the size of your current system, however if unsure you can always speak to your hardware partner to get clarity on the same. It is advised to select only those memory configurations that your hardware partners offers or which are relevant for you to consider.
2 - Incase you want to use custom size then use the custom option highlighted.
Key Points:
- Always ensure you have the latest version of the report installed on the system.
- If you are running the sizing report in development or test environment then it is likely that you might get unrealistic results which might not make sense and a possible reason would be that it might be coming due to the fact that the database itself is very small. Hence It is advisable to execute the report in PROD system to get more meaningful results which should be considered and taken forward to be more realistic.
- In scenarios such as (only upgrade of existing BW system) you don't need to choose the option "Subset/Scenario Selection".
- If you are building a BW system from scratch then you need to use SAP QuickSizer project. For more information on this please see my other post here.
- More details on this report and existing FAQ's are also listed in the SAP note 2610534 - HANA BW Sizing Report (/SDF/HANA_BW_SIZING).
Hope you find this information useful.!!
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