May 30, 2007. BLOG UPDATE: Note, the author of the papers I discussed in this blog entry has visited and commented. If nothing else, I recommend reading my follow up regarding the fact that these papers don’t even have the word Oracle in them.
It isn’t very often that you get a tier one hardware vendor directly comparing RAC with non-RAC. When it happens, it is generally by accident. That doesn’t stop me from learning from the information. I hope you will find it interesting too.
So, Dell didn’t exactly set out to compare RAC to non-RAC, but they inadvertently did. In October 2006, they released a series of whitepapers that compare Dell with Oracle to Sun with Oracle. I personally think such comparisons are a complete waste of time since Sun shops are going to run Sun and Windows shops are going to run Windows.
The whitepapers take two swipes at the Sun V490 with 8 UltraSPARC IV+ processors. The first is a cluster of Dell 2950s each with 2 dual-core Xeon 5160 (Woodcrest) processors running Red Hat Enterprise Linux 4. The second was a single Dell 6850 with 4 dual-core Xeon 7140 (Clovertown) processors running Windows 2003. Oh if only they both would have been Linux. No matter though, the comparison is still very interesting. The papers are available at the following URLs:
Even though the paper was intended to cast stones at the Sun V490, there was one particularly interesting aspect of the testing that makes the results helpful in so many other ways. See, Dell did all this testing with the same SAN. In fact, a good portion of these papers are identical. The description of the SAN used for the V490, Clustered 2950s and the 6850 appears in both papers as follows:
Storage for both the Dell and Sun servers was provided by a Storage Area Network (SAN) attached Dell/EMC CX3-80 fibre channel storage array. Each server was attached to the SAN via two QLogic Host Bus Adapters.
There we have it, 3 configurations with the same application code, the same database schema and the same database size. How tasty!
They used Dell’s DVD Store Test Application test suite that has been available since about 2005 at http://linux.dell.com/dvdstore/. I have used this workload quite a bit myself actually. It exhibits a lot of the same characteristics as TPC-C—for what it is worth. By the way, the link I provided works, the one in the whitepapers is faulty. I guess that will be my value add.
Like I said, forget about the comparison to Sun. I say look at the comparison of clustered versus non-clustered Oracle. I’ll let you read the papers for the full nitty-gritty, but the summary is worth a lengthy discussion:
Configuration Cost Throughput (Orders/Minute)
Dell 6850 $185,747 32,264
Dell 2950 Cluster $266,852 22,169
Remarkable, and remember, all the important aspects of this sort of test were constant between the two. By important I mean the application, database schema and database size and storage.
Yes, the Dell 2950 cluster theoretically offers more availability. That is important in the event of a failure, sure, but it performs at 31% less throughput than the 6850 solution when it is fully healthy. The important comparison, I believe, is the 6850 to the “brown-out” effect of running an application on a single surviving node of the 2950 cluster. With only one node surviving in the event of a failure, the 2950 cluster solution would be capable of 11,084 orders per minute—about 67% less throughput than the 6850. I think it breaks down like this; the clustered 2950 solution costs 44% more and performs 31% less but in the event of a failure, a surviving 2950 will offer about 1/3rd the throughput of a 6850.