Long response times in IT systems are not just annoying, they also slow down a company’s productivity. High-performance, high availability solutions are therefore essential. This is also true at energy provider Enso Energie Sachsen Ost GmbH in Dresden. The company group, which was formed at the start of 2006 following a merger between Enso Strom AG and Enso Erdgas GmbH, supplies more than half a million customers in the East Saxony area with electricity, water, heat, and energy-related services, such as billing services, meter services, or services for energy optimization.
The energy supplier uses SAP R/3 4.6C for billing and invoicing for small and large customers, as well as for meter management and contract account receivables and payables, and in 2001 added the SAP industry solution for utilities (formerly: SAP IS-U) to its installation. Enso creates sales statistics, extrapolations, and consolidated reports of monthly and annual figures using SAP Business Information Warehouse 3.5 (SAP BW).
The energy provider runs a system landscape with six SAP R/3 lines – that is, a combination of a development system, quality assurance system, and production system – as well as one SAP BW line. As of the start of 2003, the business software had been running on a SUSE zLinux 390 mainframe architecture with DB2 database. However, as the business volume increased, the platform reached its limits when performing certain tasks, and the upshot was long response times. This was the case for example with the extrapolation and statistics runs for queries or maintenance activities with a very large amount of customer data, as well as client copies or runs for merging business partners. The long response times caused particular problems with periodic billing for private customers in the SAP industry solution, which in some cases took up to 13 hours. There was not enough time for the overnight batch run, meaning that the data was not available at the start of dialog processing the next morning, and Enso was therefore not able to start its dialog work on time. For this reason, the company had to move some batch processing work to the weekend. On some days, performance was also insufficient for dialog work.
Instead of investing in additional hardware for the existing architecture, the company decided to migrate its 19 SAP systems to a new 64-bit Linux platform. By doing so, the energy provider wanted to lay the foundations for the planned release upgrade of the SAP solutions: the upgrade to mySAP ERP is planned for 2006/2007. More powerful servers are also an advantage for the enhancements to the SAP industry solution made necessary as a result of the German Energy Industry Act. These include the changeover to a “two-client model,” in order to separate the “grid” and “sales” areas, for example. And finally, changing from a mainframe architecture to standard servers results in lower hardware costs.
Experience from 350 migration projects in the team
The project was launched in the spring of 2005. Enso brought SAP technology specialists Realtech on board as its consulting and migration partner. The Walldorf-based service provider was chosen among other things because of the experiences it has gathered from around 350 migration projects as well as its expertise in the area of Open Source software: Realtech is co-founder of the SAP Linux Lab and is continuously involved in this meeting of experts.
Enso designed the new platform in collaboration with its consulting partner. As the energy supplier had had good experiences with SUSE zLinux (SUSE Enterprise Server 8.0) in general, the obvious decision was to use SUSE Linux Enterprise Server 9.0 on the new hardware – the company favored servers from the HP Proliant series based on x86_64 architecture. The servers were equipped with AMD Opteron processors, which Enso chose because of their good price/performance ratio. For the database, the company opted for MaxDB developed by SAP, which is very well suited for use with small and midsize SAP systems. At the same time, MaxDB offered clear cost advantages compared to other database systems. Less support is required thanks to the simple, low-maintenance operating concepts tailored to SAP, for example.
High availability through virtualization
As Realtech had been involved in the validation and release of SUSE Linux x86_64 on an AMD Opteron basis by SAP shortly beforehand, the partner was very familiar with the target platform. Enso was able to take advantage of this knowledge when it came to the question of how to realize a low-cost, high availability concept without complex cluster systems, among other things. The solution was to virtualize the application and database. For starting and stopping, the applications are addressed using virtual host names, and as a result their handling is physically independent of the server. The advantage of virtualization is that the applications and all data can be moved to a different server in the event of a system failure or insufficient hardware performance, for example. This increases system availability and reduces both the administrative work involved and the downtimes. The migration team created the necessary scripts for shutting down SAP applications on one server, moving all the associated resources to another server, and starting them up again there.
Migration was very smooth and was carried out within the planned timeframe. The weekends were available for this between October 2005 and March 2006. For each individual application, the team exported the database to the source platform, installed the SAP solution on the target platform, and imported the database. Migration had to be repeated for one SAP system because of a fault in the operating system. For the smaller systems with a database of up to 100 gigabytes (GB), the platform switch was carried out over a weekend, including the postprocessing work such as backup, modification of the interfaces, and configuration of the transport system.
For the largest SAP system, whose database had a total volume of 900 GB, a weekend was too short for all the migration activities. The project team had therefore agreed a longer downtime with users in advance. This affected the employees in all commercial and technical departments of Enso Strom AG, who were not able to work with their SAP application on the following Monday. However, during this period, they still had read access to the legacy data.
All requirements met
Once all the migration work had been completed, in April 2006, the energy supplier was immediately able to benefit from the advantages of the new platform: even though several SAP systems now share a server, the response times in both dialog work and batch processing are very good. The absolute runtimes in batch processing have been reduced by up to 50 percent.
The virtualization concept guarantees Enso high system availability at reasonable cost. In the event of failures, the Linux functionality for recovery ensures that the applications are available again quickly. Faster development and quality assurance systems make it easier to carry out test runs as well as client and system copies. The SAP Basis employees quickly got used to working with MaxDB, not least because the new database is far easier to manage.
Enso is thoroughly satisfied with the project. Overall, the new platform with its combination of SUSE Linux, MaxDB, and AMD Opteron process architecture has led to a considerable reduction in the IT costs. Above all, the changeover to standard servers has led to a drop in hardware investments and costs for maintenance and support for the system landscape. As far as Dirk Erler, system administration group lead at Enso, is concerned, the verdict is positive: “With the new solution on Linux, we have reduced our IT costs and at the same time acquired a stable and optimized SAP system.”