Identify the Performance Test Environment

The environment in which your performance tests will be executed, along with the tools and associated hardware necessary to execute the performance tests, constitute the test environment. Under ideal conditions, if the goal is to determine the performance characteristics of the application in production, the test environment is an exact replica of the production environment but with the addition of load-generation and resource-monitoring tools. Exact replicas of production environments are uncommon. The degree of similarity between the hardware, software, and network configuration of the application under test conditions and under actual production conditions is often a significant consideration when deciding what performance tests to conduct and what size loads to test. It is important to remember that it is not only the physical and software environments that impact performance testing, but also the objectives of the test itself. Often, performance tests are applied against a proposed new hardware infrastructure to validate the supposition that the new hardware will address existing performance concerns.The key factor in identifying your test environment is to completely understand the similarities and differences between the test and production environments. Some critical factors to consider are:
Hardware
Configurations
Machine hardware (processor, RAM, etc.)
Network
Network architecture and end-user location
Load-balancing implications
Cluster and Domain Name System (DNS) configurations
Tools
Load-generation tool limitations
Environmental impact of monitoring tools
Software
Other software installed or running in shared or virtual environments
Software license constraints or differences
Storage capacity and seed data volume
Logging levels
External factors
Volume and type of additional traffic on the network
Scheduled or batch processes, updates, or backups
Interactions with other systems
Source from microsoft book