Iometer IOPS Performance
Iometer is an I/O subsystem measurement and characterization tool for single and clustered systems. Iometer does for a computer’s I/O subsystem what a dynamometer does for an engine: it measures performance under a controlled load. Iometer was originally developed by the Intel Corporation and formerly known as “Galileo”. Intel has discontinued work on Iometer, and has gifted it to the Open Source Development Lab (OSDL).
Iometer is both a workload generator (that is, it performs I/O operations in order to stress the system) and a measurement tool (that is, it examines and records the performance of its I/O operations and their impact on the system). It can be configured to emulate the disk or network I/O load of any program or benchmark, or can be used to generate entirely synthetic I/O loads. It can generate and measure loads on single or multiple (networked) systems.
To measure random I/O response time as well as total I/O’s per second, Iometer is set to use 4KB file size chunks over a 100% random sequential distribution at a queue depth of 32 outstanding I/O’s per target. The tests are given a 50% read and 50% write distribution. While this pattern may not match traditional ‘server’ or ‘workstation’ profiles, it illustrates a single point of reference relative to our product field.
All of our tests used Iometer 1.1.0 (build 08-Nov-2010) by Intel Corporation to measure IOPS performance, using a SandForce-created QD30 configuration: 4KB 100 Random 50-50 Read and Write.icf. The chart below illustrates combined random read and write IOPS over a 120-second Iometer test phase, where highest I/O total is preferred:
In our Iometer tests, which use 32 outstanding I/O’s per target and a random 50/50 read/write distribution, which is generally a heavy load for SSDs but also relevant to modern hard disk drives. From these test results, we can see that five platters outperform three in input/output operational performance. This makes logical sense, because there’s less travel to fetch and ferry data. If you’re using a hard drive on any high-I/O system then I strongly urge you to consider an SSD, but if raw storage capacity is important the Seagate Desktop HDD wins our favor.
In the next section we use PCMark Vantage to test real-world performance…