Multithreaded Read & Write Patterns
The multithreaded tests simulate a situation when there are one to four clients accessing the virtual disk at the same time, the request queue depth varying from 1 to 8. The clients’ address zones do not overlap. We’ll discuss diagrams for a request queue of 1 as the most illustrative ones. When the queue is 2 or more requests long, the speed doesn’t depend much on the number of applications.
As we might have guessed from the sequential read test, the two new products from Seagate are the best at processing one read thread. The WD Caviar Black is better at two threads, though. The notable difference of the Barracuda 7200.12 series firmware shows up then, too: this HDD copes with multithreaded reading better. The Seagate Barracuda 7200.12 even returns to first place when there are even more threads to be processed: the WD Caviar Black and the others lose much speed at four threads.
Take note how similar the results of the two Green drives from WD are (thanks to identical firmware): the 2TB model is a little faster at any number of threads due to its higher recording density.
There is a clear leader at multithreaded writing: it is the Seagate Barracuda 7200.12. Our applaud goes to the authors of the new firmware. The 1.5TB model is also good enough, though.