The above chart comes from our last month’s newsletter on the lastest SPECsfs2008 file system performance benchmark results and depicts a scatter plot of system NFS throughput operations per second versus the number of disk drives in the system being tested. We eliminate from this chart any system that makes use of Flash Cache/SSDS or any other performance use of NAND (See below on why SONAS was still included).
One constant complaint of benchmarks is that system vendors can just throw hardware at the problem to attain better results. The scatter plot above is one attempt to get to the truth in that complaint.
The regression equation shows that NFS throughput operations per second = 193.68*(number of disk drives) + 23834. The regression coefficient (R**2) is 0.87 which is pretty good but not exactly perfect. So given these results, one would have to conclude there is some truth in the complaint but it doesn’t tell the whole story. (Regardless of how much it pains me to admit it).
A couple of other interesting things about the chart:
- IBM released a new SONAS benchmark with 1975 disks, with 16 interface and 10 storage nodes to attain its 403K NFS ops/second. Now the SONAS had 512GB of NV Flash, which I assume is being used for redundancy purposes on writes and not as a speedup for read activity. Also the SONAS system complex had over 2.4TB of cache (includes the NV Flash). So there was a lot of cache to throw at the problem.
- HP BL860c results were from a system with 1480 drives, 4 nodes (blades) and ~800GB of cache to attain its 333KNFS ops/second.
(aside) Probably need to do a chart like this with amount of cache as the x variable (/aside)
In the same report we talked about the new #1 performing EMC VNX Gateway that used 75TB of SAS-SSDs and 4 VNX5700’s as its backend. It was able to reach 497K NFS ops/sec. It doesn’t show up on this chart because of its extensive use of SSDs. But according to the equation above one would need to use ~2500 disk drives to attain similar performance without SSDS and I believe, a whole lot of cache.
The full performance dispatch will be up on our website after the middle of next month (I promise) but if one is interested in seeing it sooner sign up for our free monthly newsletter (see subscription request, above right) or subscribe by email and we will send the current issue along with download instructions for this and other reports. If you need an even more in-depth analysis of NAS system performance please consider purchasing SCI’s NAS Buying Guide also available from our website.
As always, we welcome any constructive suggestions on how to improve any of our storage performance analysis.