SAP load balancing is a very important aspect of using SAP packages and managing interaction within a specified server. Balancing load between two or more Netweaver AS instances requires a dispatcher which must be installed within the program. There are various ways in which balancing can be achieved. However, not all businesses have been able to achieve the correct balance that will help them effectively allocate resources. Balancing techniques and tools must be used considerately and insightfully to accomplish sought goals. Fortunately, there are various best practices that can be followed to reduce the effort of load balancing and also improve user experience.
SAP Load Balancing – Best Practices
Monitor Connection Pools
SAP load balancing heavily depends of the number of connection pools available and how users are routed across different servers. A connection pool basically refers to grouped client connections to a particular direction. The system can be activated to create automatic connection to the specified remote server or reconnect to an existing connection. Additionally, connections can be directed back to pools where they are not in use. Some of the best practices in connection pool monitoring include the following;
- Never try to increase the maximum number of connections while the system is still running. It is impossible ad will only result in delays. The best thing is to choose a maximum number that is sufficient for existing applications.
- Connection pools are usually global within the JVM (java virtual machine) and can be given any name. However, issues may arise when the conventional naming standard is not used in describing applications running within the same JVM.
- Targets created using application explorer during design-time can be used in the run-time and this is the default setting. Ensure the connection parameters and properties support the existing environment to prevent issues with targets that cannot be understood.
- Always check with your gateway administrator to know the exact maximum size of connection pools allowed for the landscape in question. To calculate your connection pool size, use the formula Time = SAP server execution time for the given function + document size + network lag.
- When dealing with larger documents or long running transactions, use a larger connection timeout parameter value. Avoid placing extensively long running documents on the foreground.
Monitoring SAP connection pools is the key to preventing run-time problems and balancing load. By default settings, a connection pool is opened when an initial request is made. When new requests arrive while the existing pool is still busy, the system automatically opens a new pool. Eventually it leads to a maximum size when no more connection pools can be opened. Any new request made during this time will call for wait time parameter which is the time the system will spend waiting for a free connection before aborting the request. Set appropriate time that allows sufficient time to reconnect instead of aborting immediately.
Log on Balancing and Registered Applications
The two ways of balancing HTTP load is through logon and registered application. Logon balancing is the most preferred method since it allows categorization of users into application server instances. This makes it very easy to increase the efficiency of a workgroup by simply setting up multiple logon groups that contain one or a couple of instances. Assigning one or more servers to specific workgroups makes it possible for users to be automatically logged on to a server that has the best performance at the moment.
The system automatically pushes users to servers with the fewest users to prevent congestion and competition for resources. Balancing by registered applications is also very effective in filtering users who are only interested in using a few routine features. When choosing a load balancing method, view user trends and select one that meets your business demands. Balancing by registered applications is more effective where large amounts of data are sent to remote locations.
Security Best Practices
Upholding high levels of security for the SAP system plays an important role in preventing unauthorized entries and backdoors that may expose you to malware and data theft. Some of the best security practices include;
- Encrypt Java connectors which are plain text by default
- Restrict users ability to access SAP gateway or monitor its activities
- Consider the use of a router to communicate with systems not within the firewall
Security impact SAP load balancing in a number of ways and malware applications are capable of slowing down the system to devastating levels. Only administrators should be able to change load balancing parameters in the gateway. Hide transaction controls such as the SM59 that affects RFC destination. This helps in hiding the IP address of all servers inside the SAP and prevents unauthorized monitoring or access.
Filtering Tools and Techniques
Load balancing is all about setting the correct configurations and parameter specifications that are sufficient for the existing environment. Since destinations configured to receive messages from a given channel will receive all messages coming through that channel, issues with configuring the business process may arise.
This is where filtering tools play an important role. Using different program IDs for distinguished messages or message splitters and filters can help in routing towards specific destinations according to message type and content. This will need coding techniques that are simple to achieve. Same program IDs may lead to message duplication and some may not be sent. However, keen caution should be enforced when dealing with IDs to ensure names are assigned in a coordinated and logical way. Encoding can also be used to map code pages to others. This aids interpretation of client language code into the server code. Reading about Unicode and non-Unicode packs as well as the limitations of each before using any is always advisable.
Balancing of server load can be the difference between most visited fast websites and slow-render irritating sites that are not loved by many. It is important to determine the maximum number of connections needed according to your SAP environment. Choose load balancing techniques that are appropriate for the specific time. When the correct parameter specifications are used and users are directed to the least busy servers, it increases connection speed. SAP load balancing must therefore be cautiously approached to prevent issues with client experience and delays in connectivity.