Resources on Demand

Consider the following scenario: The virtual outlets of an Internet shop are being inundated with customers. Hundreds of potential buyers want to know the cost of the goods in the particular version they are looking for. They enter their queries via a web browser and SAP IPC, an application in mySAP Customer Relationship Management (mySAP CRM), calculates the price. How fast a customer receives his information depends on whether enough computing capacity is available to process the large numbers of simultaneous queries.
So how many servers should companies install for their SAP IPC application? This is not an easy question as the number of queries fluctuates considerably depending on the season and the time of day. If they install enough IPC servers to handle peaks in demand without problems occurring, the Total Cost of Ownership increases and available computing capacity is wasted when demand is lower. If companies only provide a few servers, however, response times are poorer when demand is high and customers may go elsewhere.

Grid services adapt to fit requirements

The answer lies in Grid services. Based on Web services technology, they make resources available when required and distribute functionality among the available computers in the grid. Grid services are an extended version of Web services. While Web services are available statically and in a very specific volume, Grid services can be generated dynamically. When demand increases, Grid services are generated in the exact volume required and deleted again when demand falls. This means computing capacity is only tied up when it needs it to be. Dr. Alexander Gebhart, Development Architect at SAP, describes the difference between Web services and Grid services: “The principle behind Web services may be compared to a car dealer from whom I can only buy those cars that are physically present in his forecourt on an ad-hoc basis. Grid services, on the other hand, are like a factory that can build me cars immediately whenever I need them.”
The IT industry has been working on the idea of grid computing for many years. However, implementing grid computing commercially requires the use of an open standard. Such a standard is now available in the form of Open Grid Services Architecture (OGSA), introduced at the start of 2003 and supported by all leading manufacturers. This architecture not only allows functionality to be distributed among available computers, but also makes it possible to guarantee a “Quality of Service” (QoS). For example, it means that, for mission-critical applications, users can specify that Grid services are only to be generated and executed on a particular, extremely high-performance processor.

Virtual system ensures availability of computing power

The grid-compatible SAP IPC solution is the first business application to use the OGSA standard. It distributes queries to all the computers that a customer has included in the grid, regardless of the department or site where they are located. All that needs to be done to set this up is to install an OGSA-based grid component on each computer. Unlike complex standards like J2EE, OGSA is straightforward and fast to install, as it contains only the specifications required for grid computing. The grid component creates a virtual system that makes computing capacity available on demand.
The SAP IPC solution itself consists of the IPC Manager Service, the IPC Dispatcher Service and the IPC Server Service. The IPC Manager Service functions as a regulator that measures demand. The IPC Dispatcher Service distributes the queries and the IPC Server Service executes the application on the servers.

Monitoring Component
Monitoring Component

If demand exceeds a specific limit value defined by the customer, the IPC Manager Service switches on additional servers. IPC Server Services are consecutively started (i.e. automatically installed, configured and activated) on these computers until capacity utilization ceases to be at a critical level. If there is a sustained drop in demand, the Dispatcher signs off the IPC Server Service in the first instance and only completely deletes it after a certain length of time. If demand increases again in the short term, the signed-off Grid services can be quickly reactivated. A monitoring component displays at all times how many computers are available, which services are running on them and what their status is.

Cutting costs and securing a competitive edge

The benefits of this innovation for SAP customers are plain to see. “With a grid-compatible solution, companies reduce the Total Cost of Ownership of their hardware and secure a competitive edge, particularly where high performance is required. For instance, a bank can calculate financing concepts for its customers in a few hours rather than several days,” explains Alexander Gebhart.
Another advantage of Grid services is the significant drop in administration and maintenance outlay for both the hardware and the software, as developer Erol Bozak explains: “The system administrator installs the applications just once on a central server. The required number of Grid services is then generated, adapted and started automatically on the available computers. This also speeds up and simplifies upgrades by eliminating the need to install the new software version on each individual computer.

Two departments, one server pool

The pilot customer who is currently testing the grid-compatible SAP IPC solution in two departments is already profiting from significantly reduced hardware costs. Up till now, each department has been using ten of its own IPC servers, but this computing capacity was only needed if demand was extremely high. Because the peaks in demand for the two departments occur at different times, some of the servers’ capacity can be shared. Now, each department has only two of its own IPC servers with eight further servers available on a flexible basis in a shared computer pool. The company therefore now needs only twelve servers for both departments instead of its former 20, which saves around 40 % of the hardware costs.
However, this is only possible with grid-compatible software. Alexander Gebhart and Erol Bozak’s prototype has laid the foundations for grid computing in the SAP landscape. “SAP IPC is the first grid-compatible SAP solution. More will follow,” says Erol Bozak. All sectors where large volumes of data are processed are ripe for this technology, for example Financial Services or Supply Chain Management with SAP Advanced Planner & Optimizer (SAP APO) and the RFID project (Radio Frequency Identification).
Further Information about grid computing.

Sabine Höfler