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.
Once again an impressive showing by the 850 PRO, which basically cleans house here. Note that the 840 EVO's cache becomes overloaded 3/4 through this test, as indicated by the prompt drop in performance at QD=16 in our database test. In its defense, this test sequence had written 12 GB at near maximum speed by that point in the test.