IOMeter Test Results
As we've noted in our previous SSD coverage, though IOMeter is clearly a well-respected industry standard drive benchmark, we're not completely comfortable with it for testing SSDs. The fact of the matter is, though our actual results with IOMeter appear to scale properly, it is debatable whether or not certain access patterns, as they are presented to and measured on an SSD, actually provide a valid example of real-world performance for the average end user. That said, we do think IOMeter is a gauge for relative available bandwidth with a given storage solution. In addition there are certain higher-end workloads you can invoke on a drive with IOMeter, that you really can't with any other benchmark tool available currently.
In the following tables, we're showing two sets of access patterns; our Workstation pattern, with an 8K transfer size, 80% reads (20% writes) and 80% random (20% sequential) access and our Database access pattern of 4K transfers, 67% reads (34% writes) and 100% random access.
The first thing you'll note here is how flat the standard SATA SSD's performance was across test patterns and IO queue depth. The IO queue depth set in IOMeter essentially represents higher levels of workload requests of the same access patterns simultaneously. The Vertex LE SSD was saturated here as we turned up queue depth. However, the entire group of PCI Express-based SSDs scaled up significantly at higher request levels. OCZ's RevoDrive line-up flattens out at a queue of 144 or so in this test, with the RevoDrive 3 X2 putting out significantly higher IO response versus the previous generation RevoDrive and Fusion-io ioXtreme drives, but not quite catching the significantly more expensive ioDrive and LSI WarpDrive.
Our database access pattern showed much of the same performance grouping as we saw in the Workstation setup. However, with a higher write workload and smaller 4K transfers, the RevoDrive 3 X2 is further distanced from it's über-expensive SLC competitors. And that's really where the rubber meets the road here. SLC SSDs inherently have higher available write bandwidth, on average, over MLC based products, all other things being equal. However, architectural, with OCZ's SuperScale Acclerator and SandForce SF-2200 series controllers, all other things are not equal and we have one final IOMeter run we'd like to show you that demonstrates this a bit.
The workload you see represented in this graph has become a bit "industry standard" as of late, though we'd offer that it still should be taken with a grain of salt. Again, what we're looking at here is one set access pattern that is concurrently sprayed across the drive volume by IOMeter until the drive reaches its saturation point. In this IOMeter run, we should note that drives were formatted and blank and were allowed to sit idle for several hours before invoking a test, so that each drive's maintenance algorithms had a chance to maximize performance. The results here show that the RevoDrive 3 X2 is actually able to surpass Fusion-io's ioDrive by a wide margin of about 55%. Conversely, the LSI WarpDrive offers a bit more throughput beyond the RevoDrive 3 X2 as well as the FIO card.