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 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.

The red and green lines of the charts represent the same capacity of two parallel product lines both containing the Silicon Motion SM2246EN controller, and it is clear those two iterations perform identically in this test. So identically in fact that I've revised how these charts are drawn to thin out the plot lines a bit, hopefully making it easier to distinguish results that previously overlapped too much to tell which line was hidden by another for very close results.

The smaller capacity model sees slightly lower performance, particularly in tests that incorporate a percentage of writes (which are more limiting on the 256GB model). The slight advantage seen on read specific Vantage testing is highlighted further on our Web Server test, as that capacity does not see the 'dip' at QD=4-8 as was seen on the 512GB models driven by that same controller.

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