SAP BW Powered by SAP HANA- Some points to remember for Database Migration to HANA

[sunny_pahuja2]

If you are planning to migrate BW system to HANA then check below points which will help you in planning migration to HANA.

Prerequisite checks for SAP BW on HANA migration

1. If you are planning to migrate BW system to HANA and you want to perform feasibility check in order to get understanding of loading process and performance improvements then you can order this remote service from SAP. For more information, please refer to SAP note 1777465.
2. SAP HANA requires unicode. You need to perform unicode conversion prior to migration to HANA or combine migration with unicode conversion.
3. If you want to check which HANA components customer is allowed to download or List of HANA components and location for download then please refer to SAP note 1603671.
4. Before starting database migration, perform SAP HANA hardware check using script ‘HanaHwCheck.py’. For more information, please refer to SAP Note 1652078 HANA database- Hardware check. In case, Hardware check fails because of latest hardware then please check SAP note 1658845 - Recently certified SAP HANA hardware not recognized.
5. If you wish to use some external software with HANA then please check SAP Note 1730928 - Using external software in a HANA appliance.
6. When you plan to migrate SAP BW system to HANA then you need to perform hardware sizing. You can use report /SDF/HANA_BW_SIZING for sizing. Please refer to SAP Note 1736976 & 1637145 for more information.
7. In scale out architecture, sizing of master node differs than slave nodes as all system tables are stored on master node while all transactional  and master data is distributed across slave nodes. Please refer to SAP Note 1855041 for more information.
8. Before migrating to HANA, you may wish to find out which ABAP statements will be optimized for SAP HANA. Please refer to SAP Note 1847431 - SAP NetWeaver BW ABAP Routine Analyzer.
9. You want to find out what are the regular tasks for maintenance of BW system then please refer to SAP Note 1829728 - BW Housekeeping Task List.
10. For Optimal settings of SUSE Linux to run HANA system, please refer to SAP Note 1824819 - Optimal settings for SLES 11 SP2 and SLES 11 for SAP SP2.
11. Conversion of standard DSO’s in to HANA optimized DSO is no more required. Please refer to SAP Note 1849497 - SAP HANA: Optimizing standard DataStore objects. If you have already converted standard DSO's to HANA optimized DSO's then please refer to SAP note 1849498.
12. In order to check all prerequisites for HANA migration automatically, please refer to SAP Note 1729988 - SAP NetWeaver BW powered by SAP HANA - Checklist Tool.
13. Refer to SAP Note 1775293 - Migration/system copy to SAP HANA using latest SWPM 1.0 before starting migration.
14. Please check SAP Note 1715048 - BW 7.30 new features for installation or migration for latest feature in SAP BW 7.30.
15. SAP Netweaver 7.4 is also released for HANA. If you want to migrate to SAP BW 7.4 on HANA then please use SAP HANA SPS6 (minimum revision 60). SAP recommends BW standalone on NW 7.4 SP5 as it contains many new features. Please refer to SAP Note 1666670 for landscape deployment planning.
16. BI-JAVA is also available on SAP HANA now but minimum release should be SAP Netweaver 7.4 SP3. For supported combinations, please refer to SAP Note 1645590. Please refer to SAP Note 1849151 to find out supported components based on As Java  that are released for SAP HANA.
17. For latest information related to SWPM, please refer to SAP Note 1680045.
18. Please also refer to some of the key notes for SAP HANA

SAP Note 1514967 - SAP HANA: Central Note

SAP Note 1523337 - SAP In-Memory Database 1.0: Central Note

SAP Note 1732276 - High availability limitations of HANA database

SAP Note 1702224 - Disable password lifetime for technical users

SAP Note 1598623 - SAP HANA appliance software: Central Security Note

SAP Note 1702409 - HANA DB: Optimal number of scale out nodes for BW on HANA

SAP Note 1785823 - R3load/HANA: Mass import is not active by default

SAP Note 1793303 - Install and configure SUM for SAP HANA

SAP Note 1600929 - SAP BW powered by SAP HANA DB: Information

SAP Note 1715048 - BW 7.30 new features for installation or migration

SAP Note 1695112 - Activities in BW after migrating to the SAP HANA database

Migration Best Practices

1. Prior to start the migration, perform house keeping tasks to delete unwanted data from database which will help to reduce downtime for migration. Please refer to SAP Note 706478 for more information.
2. Consider Table splitting for larger tables. You can find out list of larger tables from DBACOCKPIT. You can refer to SAP Note 1783927 - Prerequisites for Table Splitting with target HANA database. Note: Database specific method for table splitting is not supported. R3ta table splitting should be used.
3. Please always use latest kernel, R3load and R3ta tools for export/import process to avoid errors.
4. In order to analyze run time of migration, please use MIGTIME tool. For more information, please refer to SAP Note 784118 - System Copy Tools for ABAP Systems.
5. In order to speed up export process, we used to prepare order_by.txt file manually but this process is no more required as this process is now integrated in MIGMON. With SWPM 1.0 SP3 PL6, variety of new options are available in SWPM where you can choose different export options like sort the export based on size or run time or repeat export without running R3szchk again. Please refer to SAP Note 1873729 for more information.
6. There are lot of new enhancements are released in report SMIGR_CREATE_DDL for HANA. Now, you can perform Table Classification (this is required for distribution and partitioning of BW tables in a scale out environment), Estimated Table Size and Row store list. Please refer to SAP Note 1921023 - SMIGR_CREATE_DDL: Corrections and enhancements for SAP HANA for more information.
7. You can utilize HANA mass import option by setting environment variable HDB_MASSIMPORT=YES to reduce time for import. Please always refer to SAP Note 1775293 - Migration/system copy to SAP HANA using latest SWPM 1.0 before using this option as there are some issues in using this option with some R3load versions.
8. Distribution monitor is not released for SAP HANA.
9. It might happen that after migration to HANA, some ABAP Code performance is not good and even slower than previous database. This might be because optimization is not done in ABAP as per recommendations. Please check SAP note 1942889 for more information.
10. SAP has released report that can help you to find the potential Infoproviders that can be retired when using HANA. Please refer to SAP Note 1908367 - SAP NetWeaver BW Transformation Finder.
11. SAP has recently released BW on HANA Migration cockpit where you can perform all tasks like sizing, DDL Generation, Checklist Tool,ABAP Optimization & Info cube conversion etc. This is very good cockpit and simpler our tasks for Pre/Post migration activities. Please refer to SAP note 1909597 for more information.

Possible errors during Migration

1. If you face “out of memory issue” during import in HANA server, please refer to SAP 1860493 - Out of memory during import migration to HANA.
2. Please refer to SAP Note 1722395 for known problems with SAP HANA.
3. If import terminates due to some SQL error then please refer to SAP Note 1782540.
4. Please refer to below SAP notes in case you face similar erros:

SAP Note 1846872 - "No space left on device" error reported from HANA

SAP Note 1787489 - SAP HANA Database: Performance Trace

SAP Note 1786918 - Required information to investigate high memory consumption

SAP Note 1747042 - Providing support access to HANA database instance

SAP Note 1740136 - SAP HANA: wrong mount option may lead to corrupt persistency

SAP Note 1897157 - Install or upgrade failed due to hdbnsutil failure

SAP Note 1894412 - SAP HANA nameserver crash after revision upgrade

SAP Note 1634848 - SAP HANA database service connections

SAP Note 1592925 - SAP HANA Studio service connection

Post Migration checks/activities

1. In case, there are some problems in SAP HANA database and you want to analyze them, Please refer to SAP Note 1641210 - SAP HANA database checking for suspected problems.
2. In order to check consistency of tables after migration to HANA, Please use report RSDU_TABLE_CONSISTENCY. For more information, please refer to SAP Note 1756099 - RSHDB: Consistency check for tables.
3. In some cases, you will face problem where clients are not able to connect to SAP HANA scale out nodes. This might be due to how scale out architecture is configured. Please refer to SAP Note 1743225 - HANA Potential failure of connections with scale out nodes.
4. Please refer to SAP Note 1734333 - BW Pre and Post Upgrade and Migration Tasks.
5. As of SAP Netweaver 7.4 release, Declustering of tables while migrating to HANA database is supported (Refer to SAP Note 1905134). In SAP Netweaver 7.4, you can run report SHDB_MIGRATION_CHECK to perform various checks like declustering, depooling and indexes etc. Refer to SAP Note 1785060 for more information.
6. If you want to check compatibility of 3.x data flow with BW on HANA then please refer to SAP note 1686378.
7. You can transport InfoCubes from source system (non-HANA database) to BW on HANA system but there are some prerequisites to it. Please refer to SAP note 1691096 for more information.
8. After migration is complete, It is recommended to implement important SAP notes prior to productive use of your system. In order to get list of all SAP notes, there is attachment attached to SAP note 1846493. This note is periodically updated, please check latest version of this note.

HANA Revision Upgrade

1. If you are planning to upgrade SAP HANA to SP6 then please note that SUM for SAP HANA will be replaced by SAP HANA Lifecycle manager (HLM). You can still use SUM in HANA SP6 but its functionality will be very limited. For more information, please refer to SAP Note 1836498.
2. For older releases i.e. till SAP HANA SP5, you can use SAP Note 1793303 to configure SUM for SAP HANA.

Performance Optimization

1. In order to assess memory consumption of HANA database, please refer to SAP Note 1698281 - Assess the memory consumption of a SAP HANA System.
2. If you are experiencing slow performance of HANA database, Please check whether it is because of CPU or not. For more information, Please refer to SAP Note 1890444 - Slow HANA system due to CPU power save mode.
3. Row store memory is a lot bigger than actual data size because row store tables grow by allocating a 64 MB segment and also, shrinks by same. If you have deleted lot of data from row store tables and then a lot of sparse segment will be present. And in order to free up the space, reorganization will be necessary. For more information, please refer to SAP Note 1813245 - SAP HANA DB- Row store reorganization.
4. If you want to identify problems related to primary keys and unique constraints then please refer to SAP Note 1666976 - uniqueChecker usage description.
5. In case you find out that some tables are not partitioned or distributed correctly over several HANA nodes, please follow SAP Note 1792096 - HANA Scale-out landscape, BW table partitions not distributed.
6. In order to optimize select statement for all entries, please refer to SAP Note 1662726 - Optimizing select with FOR ALL ENTRIES in SAP HANA database.
7. In order to optimize performance on HANA then it is important that data that is rarely accessed or no longer needed should not be loaded into main memory. And for that, you should understand concept of non active data in BW. Please refer to SAP note 1767880 for more information.
8. If you are facing memory related problems or getting alerts for memory consumption in HANA then in order to analyze the problem in detail, Please refer to SAP KBA 1840954.

SAP has recently introduced tool called DMO with the help of which you can combine upgrade and migration to HANA in a single step. There are certain restrictions to use this tool, please refer to SAP Note 1799545 for more information. SAP Note 1799545 also contains attachment which shows source and target version path for upgrade and migration.

This is not the final list of all activities to carry out migration to SAP HANA and you need to refer to system copy guide, SAP release notes and SCN etc. for detail process. Please refer to SAP Note 1599888 - SAP HANA: Operational Concept.

Check guide for Best Practice Guide - Classical Migration of SAP NetWeaver AS ABAP to SAP HANA

Latest Updates

1. SAP introduced Support for SAP ABAP Application Server installation on HANA server. Now, you can install ASCS/ERS/PAS on HANA server and it also supports HA installation of SAP on HANA Server. This is available as of SAP HANA SPS7 for single node installation and products based on SAP Netweaver 7.4. Please refer to SAP 1953429 - SAP HANA and SAP NetWeaver AS ABAP on one Server and installation guide attached to this note.
2. Now, you can combine Unicode Migration (for Single Code Page Systems) with DMO procedure. This feature is available from SUM 1.0 SP10. Please refer to SAP Note 1799545 for more information.
   

Cheers..

Sunny

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