IOMeter – IOps
Iometer is an I/O subsystem measurement and characterization tool for single and clustered systems. It was originally developed by the Intel Corporation and announced at the Intel Developers Forum (IDF) on February 17, 1998 – since then it got wide spread within the industry.
Meanwhile Intel has discontinued to work on Iometer and it was given to the Open Source Development Lab (OSDL). In November 2001, a project was registered at SourceForge.net and an initial drop was provided. Since the relaunch in February 2003, the project is driven by an international group of individuals who are continuesly improving, porting and extend the product.
We are running new version of IOMeter, but with a similar configuration as compared with prior versions (i.e. compressibility of data, etc), as to maintain consistency across the test data pool.
Light desktop usage sees QD figures between 1 and 4. Heavy / power user loads run at 8 and higher. Most SSD's are not capable of effectively handling anything higher than QD=32, which explains the plateaus.
Regarding why we use this test as opposed to single-tasker tests like 4KB random reads or 4KB random writes, well, computers are just not single taskers. Writes take place at the same time as reads. We call this mixed-mode testing, and while a given SSD comes with side-of-box specs that boast what it can do while being a uni-tasker, the tests above tend to paint a very different picture.
As hinted earlier during the HDTach runs, the SSD 730 demonstrates excellent low-latency and high-IOPS performance at low queue depths. While the 730 does fall off earlier than the competition, it is less likely to enter those higher QD regions as it would have been able to power through the stream of IO requests at a faster rate earlier in the game (i.e. higher QD's are usually a result of requests 'piling up' on the SSD, and the 730 is less likely to let them do so in the first place).