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SSDs In RAID: A Performance Scaling Analysis

Benchmark Results: I/O Performance

The Iometer benchmark and its File Server, Web Server, and Workstation benchmarks illustrate how the system scales. While a single SSD reaches approximately 15 000 I/O operations per second, a RAID 0 array with two drives gets an additional 10 000 I/O operations. Adding more SSDs increases the total I/O capabilities by roughly the same number.

Each added SSD not only increases capacity, but I/O performance grows strongly and steadily as well. The test system does not seem to be nearing any upper limit of I/O performance, but scales with the same amount for each drive added. Using traditional magnetic hard drives, such performance is only reached by adding a really substantial number drives (in the double-digits). Or, to put it differently, where you once had to add several new servers or huge RAID arrays, buying another SSD might be enough in today's landscape.

The Database benchmark falls somewhat out of place, as a single SSD should achieve better performance. The trend still remains the same, though, with a five-drive RAID 0 array providing much higher I/O throughput.