Performance Terminology
The following table defines the performance terms used in Commerce Server Help.
| Term | Definition |
|---|---|
| ASP (Active Server Pages) | Pages of information transmitted by the Web server to the client's browser. ASPs are the building blocks of user operations and the primary unit of measure for Web Server performance (ASP requests/sec). |
| context switching | The rate at which one thread is switched to another (either within a process or across processes). |
| CPU cost | CPU resources needed to perform a single shopper operation. |
| DC | Domain Controller |
| MSDTC | Microsoft Distributed Transaction Coordinator. A transaction manager that enables client applications to include several different sources of data in one transaction. MSDTC coordinates committing the distributed transaction across all the servers enlisted in the transaction. |
| frequency | Operations performed per second by a single shopper. |
| MSCS | Microsoft cluster service combines two servers to increase the availability of a service. |
| MTBF | Mean time between failure. |
| NIC | Network interface card. |
| NLB | Network Load Balancing is a feature provided with Microsoft Windows 2000 Advanced Server to provide scalability and reliability. |
| OLAP | Online Analytical Processing |
| optimal performance | The highest measured performance for a specific shopper Operation with the lowest measured CPU cost.
The CPU cost increases geometrically when context switching exceeds 15,000/sec. Hence, optimal performance measurements are taken before context switching hits this threshold. |
| Pentium III equivalent MHz (P3EM) | A unit of measure for processor work. 800 Pentium III equivalent MHz (P3EM) is delivered by a 800 MHz Pentium III processor. A computer with two 800 MHz Pentium III processors will deliver a maximum of 1600 P3EMs. |
| Pentium III Million Clock Cycles (P3MC) | The number of cycles that a Pentium III chip used in order to process an operation. For example, if an 800 MHz PIII server performed 1 request per second at 10 percent CPU utilization, then the request required 80 million Pentium III Clock cycles to complete. Similarly, if a large operation required 10 seconds of the same CPU running at 99 percent utilization, that operation required 0.99 x 10 x 800 million Pentium III Clock Cycles to complete. |
| RAID | Redundant Array of Inexpensive Disks. |
| SAN | Storage Area Network is a hardware solution to provide a richer storage solution. |
| SPOF | Single point of failure. |
| user | A user connected to a Commerce Server site by a Web browser. |
| user operation | An action performed by a user while visiting the site, such as browsing products, adding a product to the shopping basket, and purchasing a product. |
| user profile | A description of user behavior created by the capacity planning expert that is used to project user capacity of the system. The user profile is constructed of a series of user operations in specified proportions within a given period of time. |
| TCA | Transaction Cost Analysis, a method for calculating the capacity of an Internet site. |
| uptime | Percentage of time the Web site responds to end user requests. |
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