Power7 Blades: The i/DB2 Combo Versus AIX/Oracle
May 3, 2010 Timothy Prickett Morgan
Major Correction: In this story, I made two errors. The biggie is that I thought the price to activate either i 6.1 or i 7.1 per core on the new Power Systems 701 blade server was $2,250 a pop plus $250 per user, as it is on the Power Systems 700 blade, since both are single-socket blades. Nope. The PS701 blade has the same ridiculous price as the two-socket PS702 blade. So my analysis below is for the PS701 is not correct. I also thought, through vaguary on IBM’s Web site, that the AIX licenses for the Power7 blades were per core when they were per blade. This didn’t change the numbers all that much, but the i pricing sure did for the PS701. I have updated this analysis and the price/performance table in the May 10 issue, which you can read here.
IBM sure doesn’t like to make it easy for customers to figure out the relative bang for the buck its various platforms offer. And it never has in the more than two decades I’ve been at this game. With the advent of the Power7-based blade servers, this has not suddenly or miraculously gotten easier. But despite the difficulty of trying to come up with an apples-to-apples comparison, I think it is safe to say this: In many cases, the premium that IBM is charging i For Business shops for configured Power7 blade servers is reasonable compared to what it costs to configure AIX and an Oracle database on the same identical blades.
This is progress. And it is surprising.
As I explained in last week’s issue of The Four Hundred, the Power Systems 700, 701, and 702 blade servers announced earlier in April offer much better bang for the buck than the Power6+ JS23 and JS43 blades they replace, but it is hard to beat the pricing on the original single-socket JS12 blade from two years ago when it comes for bang for the buck on i 6.1 or i 7.1. (That blade had some I/O bandwidth and memory capacity issues, mind you, so nothing is perfect.)
Of the many comparisons that need to be done to compare the PS700, PS701, and PS702 blades running i 7.1 to the Windows, Linux, and Unix alternatives out there on the market, the most obvious first one is to see how IBM’s own AIX Unix lineup stacks up running the most popular database on AIX and on the other two Unix platforms, HP-UX and Solaris. That would be Oracle’s database, the most recent version of which is 11g. On these machines, Oracle offers a very inexpensive version of its database called Standard Edition One. The SEO variant of 11g (like the 9i and 10g versions ahead of it) is licensed on servers with one or two processor sockets only. The PS700 and PS701 both have only one socket, and the PS702 is just two PS701s slapped together to make a two-socket, double-wide blade. So SEO, which costs $180 per named user or $5,800 per processor core, is appropriate for these blades. The Oracle 11g Standard Edition database, which can span larger servers, costs $17,500 per core or $350 per named user. There is no reason to put 11g Standard Edition in any of these blades.
So is AIX Standard Edition, which costs $2,000 per core on the PS700 compared to $1,200 per core for the Express Edition, which is limited to four cores. Express Edition is really only useful on a machine if you want to run infrastructure workloads and partition up a machine, or have small database images. So I didn’t bother with it. AIX Standard Edition costs $4,000 per core on the PS701 blade and $8,000 per core on the PS702 blade.
In my comparisons, the flat pricing of AIX mimics the flat OS fee IBM charges for i 7.1 on these blades, and the named user pricing from Oracle mirrors the per-user fee to access the DB2 for i database. I tried to make the comparisons as similar as possible.
As in last week’s comparison, the i 7.1-DB2 for i comparison to AIX-11g on the Power7 blades takes the hardware shown in this monster comparison table and adds the number of users shown to the system. Pricing does not include support fees, but includes the BladeCenter chassis, the blade, its memory, disk storage, operating system, and database software.
More for fun than anything else, I have thrown in estimated throughput on the TPC-C online transaction processing benchmark test. As you well know from reading The Four Hundred, IBM’s Commercial Workload Performance (CPW) relative performance metric is based on the TPC-C test, and you can get a rough idea how an AS/400, iSeries, System i, or Power Systems i machine would do on the TPC-C test by multiplying the CPW number by 9.95. The relative performance (rPerf) test used on the AIX side of the Power Systems house is also based on TPC-C, and you get estimated throughput (in transactions per minute) by multiplying rPerf by 10,250. In the early 2000s, the AIX-Oracle combination showed about a 10 percent performance edge over OS/400-DB2. But as I explained with the Power5+ machines, the gap opened way up–like 65 percent. And the gap is getting larger, as you will see in the table I have created. I don’t think this gap is real. I think IBM’s AIX TPC-C benchmarketeers have partitioned and de-randomized the TPC-C benchmark in some way that it runs like a top on the test and yet does not break the rules–a technique that the i folks have not used. I can’t prove it, but other benchmarks do not show such a wide gap between the platforms, and IBM never answers direct questions about this discrepancy. Which means something is fishy.
I would be very surprised if on machines with fewer than 32 cores and 64 threads there is more than a 10 to 20 percent performance advantage to using AIX with either DB2 or Oracle databases compared to the i-DB2 combo. Recent Java tests I told you about in late March for Power7 iron running AIX and i suggest it is about 20 percent. There is no way the gap is as large as CPW and rPerf suggest.
If you compare the two platforms on the Power7 blades, the i version is usually more expensive. On PS700 blades, the premium on a per-user basis ranges from 4 percent to 19 percent, and the gap gets wider as the machine is loaded up with users. That’s the effect of i 7.1 costing a little more per core and per user fees being 40 percent higher ($250 for i compared to $180 per user for the Oracle SEO database). It adds up. In some cases on the PS701 blade, as you will see, the i-DB2 variant is actually less expensive than the AIX-Oracle duo. And because of the very high price for the base i 7.1 license on the 16-core PS702 when fully loaded with software compared to AIX, that box has a premium well above 50 percent. Which is ludicrous. AIX 6.1 only costs $8,000 per core on this machine, and it is hard to argue that i 7.1 is worth $14,995 per core. On the PS700, i 7.1 costs $2,245 per core and AIX Standard Edition costs $2,000 per core. This is the kind of gap the market can tolerate. And therefore, this is the kind of price difference on larger Power7 blades that i shops should demand.