Performance during Multi-Threaded Writing / Reading
In this pattern we test the controller’s ability to perform multi-threaded sequential writing/reading by emulating simultaneous workload on the storage subsystem imposed by a few applications that have requested “large files”. The special test agent of the IOMeter program that will emulate the above mentioned applications (in Intel IOMeter terms it is called Worker) reads/writes a sequence of 64KB blocks of data starting with some initial segment. By increasing the number of outgoing requests from the Worker (from 1 to 8 with the increment equal to 1) we study how well the controller can reorganize and arrange requests (i.e. combine several requests for sequential data into a single request). Raising the number of simultaneously running Workers, we make it harder for the storage subsystem, because in real-life situation several simultaneously working programs will compete with one another for the priority access to the hard disk drives. Each Worker processes its own data (i.e. the addresses of the requested data blocks do not coincide by different Workers).