Tuesday, March 04, 2008

Various types of performance testing

Came across this site (http://www.loadtest.com.au/types_of_tests.htm) that lists down the various types of testing that can be done to performance test a system. Given below are snippets from the above page.
  1. Load Testing: Load Tests are end to end performance tests under anticipated production load. The primary objective of this test is to determine the response times for various time critical transactions and business processes and that they are within documented expectations (or Service Level Agreements - SLAs). The test also measures the capability of the application to function correctly under load, by measuring transaction pass/fail/error rates.
  2. Stress Testing: Stress Tests determine the load under which a system fails, and how it fails. This is in contrast to Load Testing, which attempts to simulate anticipated load. It is important to know in advance if a ‘stress’ situation will result in a catastrophic system failure, or if everything just 'goes really slow'. There are various varieties of Stress Tests, including spike, stepped and gradual ramp-up tests. Catastrophic failures require restarting various infrastructure and contribute to downtime, a stress-full environment for support staff and managers, as well as possible financial losses.
  3. Volume Testing: Volume Tests are often most appropriate to Messaging, Batch and Conversion processing type situations. In a Volume Test, typically the Response times are not measured. Instead, the Throughput is measured. A key to effective volume testing is the identification of the relevant capacity drivers. A capacity driver is something that directly impacts on the total processing capacity. For a messaging system, a capacity driver may well be the size of messages being processed. For batch processing, the type of records in the batch as well as the size of the database that the batch process interfaces with will have an impact on the number of batch records that can be processed per second.
  4. Network Testing: Network sensitivity tests are tests that set up scenarios of varying types of network activity (traffic, error rates...), and then measure the impact of that traffic on various applications that are bandwidth dependant. Very 'chatty' applications can appear to be more prone to response time degradation under certain conditions than other applications that actually use more bandwidth. For example, some applications may degrade to unacceptable levels of response time when a certain pattern of network traffic uses 50% of available bandwidth, while other applications are virtually un-changed in response time even with 85% of available bandwidth consumed elsewhere.This is a particularly important test for deployment of a time critical application over a WAN.
  5. Failover Testing: Failover Tests verify of redundancy mechanisms while under load. For example, such testing determines what will happen if multiple web servers are being used under peak anticipated load, and one of them dies. Does the load balancer react quickly enough? Can the other web servers handle the sudden dumping of extra load? This sort of testing allows technicians to address problems in advance, in the comfort of a testing situation, rather than in the heat of a production outage.
  6. Soak Testing: Soak testing is running a system at high levels of load for prolonged periods of time. A soak test would normally execute several times more transactions in an entire day (or night) than would be expected in a busy day, to identify and performance problems that appear after a large number of transactions have been executed. Also, due to memory leaks and other defects, it is possible that a system may ‘stop’ working after a certain number of transactions have been processed. It is important to identify such situations in a test environment.