Jazz Disk Bench Lite is a utility application designed for accurately measuring the performance of storage devices on iPhone. This tool supports both sequential and random read and write tests, providing insights into the speed and efficiency when copying large files. Additionally, it offers stress testing capabilities ranging from 2-100GB to evaluate storage stability and measure disk speed under varying loads.

The Sequential Test in Jazz Disk Bench Lite involves reading or writing 16MB data sequentially, while the Random Test focuses on 4 KB block operations in random locations, crucial for assessing device performance. The Stress Test feature allows users to write large data sizes sequentially, aiding in determining storage stability and disk speed when cache limits are reached.