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 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. You can also click the following links for the full results:

• IOMeter: Multithreaded Read
• IOMeter: Multithreaded Write

When there is only one read thread, the Seagate 7200.1, the oldest of the drives, is slow due to its low recording density. The 200GB Seagate 7200.2 is an obvious leader. Interestingly, the 160GB Seagate from the same series is slower by about 10%.

When there are two or more read threads, the Seagate drives suffer a terrible performance hit. The Hitachi and Fujitsu slow down, too, but not as much as their opponents.

Seagate’s drives are not as hopeless at multithreaded writing as at reading, though. The Fujitsu is ahead with one thread and is followed by the Seagate products (ranked according to their capacity) and the Hitachi. When there are more write threads to be processed, the Fujitsu slows down, giving way to the Seagate 7200.2 models. The Hitachi is the slowest irrespective of the number of write threads. It is even inferior to the Seagate 7200.1 that has lower-density platters.