Testing of a system logging facility using randomized input and iteratively changed log parameters

A method and computer program product for testing a system logger. Randomized input is provided into a logging facility and automated testing of the logging facility is performed in a multi-processing environment. Self-verification of data retrieved from the logging facility is performed to ensure no data loss occurs due to external system events or failures driven by a test tool. Real-time analysis of results received is performed by the test tool based on the randomized input into the logging facility. First failure data is captured and self-verification of results of a data recovery operation of the logging facility is performed in a disaster recovery scenario. Self-verification includes writing log blocks of random sizes to the log stream, iteratively forcing log data to be offloaded from primary storage to secondary storage, iteratively updating log stream attributes, and iteratively swapping duplexing modes.