Multi-Thread Read & Write Patterns
The multithreaded tests simulate a situation when there are one to four clients accessing the hard disk at the same time – the clients’ address zones do not overlap. We will 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. You can also click the following links for the full results:
Ranking up according to the sequential speed when reading one thread, the HDDs do not change this order when processing multiple threads. The efficiency varies, though. The Hitachi C10K300 suffers more from the multiple threads than the other HDDs. The Seagate 10K.1 degenerates into random reading with very low performance at two and more threads. Alas, this behavior was typical for an entire generation of Seagate drives and we see it again now.
It is only with the single thread that the HDDs are ranked up like in the sequential write test. The Seagate 15K.1 is an exception, probably because it lacks deferred writing. The Seagate 10K.1 falls behind at two threads, too. This HDD seems to dislike multithreaded loads. A funny thing happens to the Hitachi C10K300. This drive survives the addition of a second thread easily but slows down heavily at three and four threads, falling behind its predecessor Hitachi C10K147.