This chart is from SCI’s last months report on recent Storage Performance Council (SPC) benchmark results. There were a couple of new entries this quarter but we decided to introduce this new chart as well.
This is a bubble scatter plot of SPC-1(TM) (online transaction workloads) results. Only storage subsystems that cost less than $100/GB, trying to introduce some fairness.
- Bubble size is a function of the total cost of the subsystem
- Horizontal access is subsystem capacity in GB
- Vertical access is peak SPC-1 IOPS(TM)
Also we decided to show a linear regression line and equation to better analyze the data. As shown in the chart there is a pretty good correlation between capacity and IOPS (R**2 of ~0.8). The equation parameters can be read from the chart but it seems pretty tight from a visual perspective.
The one significant outlier here at ~250K IOPS is TMS RAMSAN which uses SSD technology. The two large bubbles at the top right were two IBM SVC 5.1 runs at similar backend capacity. The top SVC run had 6 nodes and the bottom SVC run only had 4.
As always, a number of caveats to this:
- Not all subsystems on the market today are benchmarked with SPC-1
- The pricing cap eliminated high priced storage from this analysis
- IOPS may or may not be similar to your workloads.
Nevertheless, most storage professionals come to realize that having more disks can often result in better performance. This is often confounded by RAID type used, disk drive performance, and cache size. However, the nice thing about SPC-1 runs, is that most (nearly all) use RAID 1, have the largest cache size that makes sense, and the best performing disk drives (or SSDs). The conclusion cannot be more certain – the more RAID 1 capacity one has the higher the number of IOPS one can attain from a given subsystem.
The full SPC report went out to our newsletter subscribers last month and a copy of the report will be up on the dispatches page of our website later this month. However, you can get this information now and subscribe to future newsletters to receive future full reports even earlier, just email us at SubscribeNews@SilvertonConsulting.com?Subject=Subscribe_to_Newsletter.
As always, we welcome any suggestions on how to improve our analysis of SPC or any of our other storage system performance results. This new chart was a result of one such suggestion.