Multi-Threaded Read & Write Patterns
The multi-threaded tests simulate a situation when there are one to four clients accessing the hard disk at the same time. The depth of the outgoing request queue is varied from 1 to 8, and the address zones of the applications (called Workers in IOMeter) do not overlap.
You can follow the links below to see tables with results, but we’ll discuss diagrams for a request queue of 1 as the most illustrative ones. When the queue is longer, the speeds depend but little on the number of applications.
The drives with the highest recording density expectedly take top places when reading one thread but the situation changes dramatically when there are two read threads. Western Digital’s drives are the favorites now. We’ve got the same performance with any of the four models, including the two drives from the RE2-GP series that have a lower spindle rotation speed. The Hitachi and the new drives from Seagate pass the test successfully whereas the older drives from Seagate and the Samsung suffer a terrible performance hit.
The drives all slow down proportionally at three threads, the Hitachi being the only drive to have a heavier performance hit than the others. The addition of a fourth thread provokes changes in the standings. It looks like Seagate’s 7200.11 and ES.2 drives catch a second wind: they win first places as the consequence. The older drives from Seagate and the Samsung feel equally bad at any number of threads other than one.
It is different with multithreaded writing. We’ve got new leaders: the Samsung and the Hitachi. The former even accelerates when switching from one to two threads. Then, the new drives from Seagate are surprisingly slow. They have the lowest speed here, being outperformed by the older models from Seagate. Take note that the server versions are somewhat faster than their desktop counterparts.
The Samsung is 15MBps faster than the closest pursuer at three and four threads. Interestingly, Seagate’s 7200.11 and ES.2 are again somewhat faster at four than at three threads.