There are several aspects involved in delivering high I/O performance to parallel applications, from hardware characteristics to methods that manipulate workloads to improve achievable performance.
Running the same application with different I/O configurations gives the possibility to tune the I/O system according to the application access pattern.
One way to predict application performance in HPC systems with different I/O configurations is by using modelling and simulation techniques. Modeling the system allows assessing obtained performance and therewith estimate the performance potentially gained by optimizations.
File systems are implemented in the operating system which deploys strategies to improve performance such as scheduling, caching and aggregation. Therefore, the observable I/O performance depends on more than the capabilities of the raw block device.