IOMeter v2006.07.27 – 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.

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.

Now for the results. We can identify some obvious pairings here. First the VR takes the lead with its high spindle speed and lightweight head pack. Then we have the Black and RE4 – both 7200RPM drives. The RE4-GP stands alone just below, but can keep above the Greens with faster seeks and other enterprise optimisations. Then we have the EZRS / EZRX Greens, both nearly identical drives minus interface speed. Finally at the bottom we have the Red a near match to the AV-GP. This makes sense as this test is driven primarily by access time, and since the Red favors silence and longevity over performance, we see it near the bottom. To be clear, a home NAS will rarely (if ever) see this sort of workload.

Be advised that if you perform this type of test on the Red, accesses *must* be 4K aligned (due to the advanced format employed by the drive).

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