Bang for the Buck: Baby i5 Servers Versus Windows and Linux Boxes
July 31, 2006 Timothy Prickett Morgan
Ever since IBM announced a revamped Power5+ System i5 line in late January, I have been itching to put together price/performance comparisons with Windows, Linux, and Unix platforms to get a sense of how the new i5s compare to these alternatives in the entry, midrange, and high-end of the server market. But, with so many new processors and server designs coming out the door this summer, I thought it best to wait until everything was out.
So now, Intel has its dual-core “Woodcrest” Xeon 5100s and its dual-core “Montecito” Itanium 9000 processors out, and they are making their way into servers. AMD is a week or two away from getting its “Santa Rosa” Rev F Opteron processors to market, and IBM is expected to put the finishing touches on its Power5+ rollout in the System p5 AIX server line (rejiggering some entry machines) and has the Power5+ chips inside its p5 590 and 595 big iron boxes. The major server makers have put Woodcrest machines into the field, Sun Microsystems has a reasonably broad “Galaxy” Opteron server line out, and Hewlett-Packard, Unisys, NEC, and Fujistu-Siemens are doing the final testing on their Montecito boxes. Intel is also pulling its dual-core “Tulsa” Xeon MP processors ahead into the third quarter for four-socket and larger servers, in an effort to kick some wind out of AMD in the lucrative midrange and high-end X64 market. While things are still moving around a bit, the server chips and platforms have stopped moving around so much. We can talk about how various platforms stack up against each other and the data won’t be useless in a month or so.
Going through all of the various comparisons will take some time, of course, because the server market is getting a little more complex now that virtualization has entered the picture and Linux is a viable alternative to i5/OS, Windows, and Unix, which have dominated database and application processing for a long time. In this week’s installment of the Bang for the Buck series, I am starting out on the smallest System i5 machines, which are the i5 Value Edition and the various pre-configured Express Editions. There are four different Value Editions and six different Express Editions, so I tried to pick representative configurations. Then, I went out to the HP site and configured Celeron D and Xeon 5100 machines that were as similar to these i5 machines as I could find. I put a Windows stack on these HP machines, and then a Linux stack. I even went so far as to make a light stack (using the cheapest Windows or Linux operating system, database, and hypervisor as I could) and a heavy stack (using the enterprise-class equivalents that most closely match the i5/OS stack). The light stack is what I think companies who buy baby servers will buy, while the heavier stack (which is the Windows #1 configuration in the tables I have built) is the industrial-grade stuff with the most features and scalability. I then configured two Sun Galaxy boxes with Windows just to show you how aggressive Sun is these days.
You can see these all of these baby server configurations in this monster table I have created.
The machines in the table have the hardware features shown. Note: IBM is gearing down the performance of the 1.9 GHz Power5+ chips until you turn on the Accelerator feature (which costs $13,499). The OLTP performance of the Celeron D processor (which oddly has only one core even though it has a D in its name, which just goes to show that Intel is, in many ways, losing it) is based on a wild guess on my part, since no one has done TPC-C performance measurements on this machine. That’s why I marked it in red. I am more confident of the estimates for performance I made on the Woodcrest servers, since there have been some tests. Be careful if you think the Opteron machines I show can whoop the Woodcrests. The 1.86 GHz Woodcrest chip, technically known as the Xeon 5120, is not the fastest part; the Xeon 5160 ramps up to 3 GHz and can do about 60 percent more work. I have put a RAID 5 disk controller on each machine and put 2 GB of main memory on them. I put either two or four disks in them, depending on what the i5 configurations were doing. Each server also has a basic tape backup, which IBM includes and which other vendors do not.
As always, I have added just the base operating system and database to the configurations, but this time around, I am throwing in virtual machine or logical partitioning hypervisors, since I think people are going to start using these in production. The i5 has had such software embedded for two years, and to make it a fair comparison, this functionality should be added to X64 servers as well. For the heavy configurations of the Windows and Linux machines in the table, I added in VMware‘s top-of-the-line ESX Server 3 with all of the bells and whistles. And for the cheapo configurations, the Windows boxes have Microsoft’s freebie Virtual Server 2005, while the Linux machines, which are configured with Novell‘s just announced SUSE Linux Enterprise Server 10, have the integrated and free Xen 3 hypervisor from XenSource. I put SQL Server 2005 Workgroup Edition or Standard Edition on the Windows machines, and Oracle Standard Edition One on the Linux boxes.
The first thing you will notice in the table is that it is very hard to build a server that is geared down like the i5 Value Edition with 600 CPWs of power is. Only about 15 percent of that box is actually doing any useful work, the way that IBM gears it down with governors. (I am assuming, of course, that the database and applications running on these machines do not hit the 5250 protocol, since they have very minimal green-screen processing capabilities. Assume that the software is using one of the many tools that get around the 5250 problem that have been sanctioned by Big Blue.) Cutting back to the slowest Celeron D processor in a ProLiant DL320 G4 server, this box can deliver more than twice the performance of the initial i5 Value Edition configuration. The price/performance of this i5 Value Edition is $2.12 per TPM. If you accelerate this box, you can crank up the performance to just under 31,000 TPM and the price goes up to $26,132 for a box with two disks and 2 GB of memory. But the performance bump is so big that the bang for the buck of this configuration is a pretty healthy 85 cents per TPM. If you go for the Express Entry Plus RAID configuration IBM offers, which has two more disks and a RAID 5 controller, this is actually a worse deal than the initial Value Edition, by the way. Go figure.
While the accelerated Value Edition offers good price performance, and better than the heavier software stacks on the HP iron running Windows and Linux, moving to the freebie hypervisors and, on the Windows platform, SQL Server Workgroup Edition from Standard Edition, gives the Windows and Linux platforms a substantial lead on entry servers in terms of price/performance.
Here’s another thing to notice. I cannot find enough benchmark data to prove this, but as best as I can figure, there are no substantial performance or scalability differences on entry or midrange machines running either Linux or Windows when it comes to database performance. There is so little data that I can’t really prove it one way or the other, to be honest. So I have assumed that they are the same, just as Windows and Unix on larger iron (where the two are run side-by-side, such as on Itanium iron) do not seem to show more than a few percent of wiggling on performance.
As you can see from the tables, the un-accelerated Value Edition and Express Edition i5 520 machines more closely resemble the price/performance and performance of the Celeron-based HP server running the heavier Windows software stack (Windows Server 2003 Enterprise Edition, SQL Server 2005 Standard Edition, and ESX Server 3). However, those Windows and Linux machines cost a little less and offer (I believe) slightly higher performance, which means they bring better value for the dollar for smaller workloads. Still, given the uncertainty of the performance estimate, I would be willing to concede that this could be a wash.
However, when you look at a Woodcrest machine in the same price range as these 1,200 CPW Value Edition and Express Edition boxes, even running the heavier software stack, these Woodcrest machines just blow the i5s away. For the same money, you get nearly four times the performance, and adding a second processor (which means two more cores) will nearly double performance and not increase software prices except for the per-socket database fees, which means several thousand dollars. The Value Edition and Express Edition machines have one core. No mas. You run outta gas, you need to go buy a plain vanilla i5 520, and those are, by comparison, very expensive. It takes $21,000 to activate i5/OS (which includes DB2/400) on one core in the i5 520 boxes. This is a lot better than the $45,000 IBM was charging last year, but it is egregious compared to the generosity in the Windows and Linux world.
If you do the smart thing and accelerate the Value Edition or choose the Express Turbo configuration (which also allows the full CPW capacity of the single Power5+ core to run i5/OS), you can get a box that offers similar performance to a Woodcrest box with a single, dual-core chip in it. But that i5-i5/OS-DB2/400-Virtualization stack is about 40 percent more expensive than the heavy Windows software stack, and about 2.5 times as expensive as the cheapo Windows stack.
The interesting thing to me is how aggressive Sun is with its pricing on the Galaxy machines. As best I can figure, the Sun Galaxy machines are offering very good bang for the buck, and I suspect that the HP ProLiant line with Opterons and indeed anyone else’s Opteron machines would show similar bang for the buck. There is a reason why AMD has Intel freaked out, after all. Having said that, the Galaxy X2100 machine has no expandability at all, and is not really appropriate except for very small workloads. Also, the Galaxy X4200 server I configured has a single-core Opteron 248 processor, which is the slowest chips I could put in the box that Sun currently sells. With two of these chips, I reckon this machine can do nearly twice as much work as a single-core Value Edition or Express Edition machine with one 1.9 GHz Power5+ core activated. While the performance and price/performance of these machines are great, there is no more room to put any storage in the box in either case. And that is not a good server for running databases and applications.
Sun should have offered Galaxy tower configurations with more memory and disk expansion if it wanted to sell into the SMB space. These rack-mounted Galaxy machines are really aimed at infrastructure, supercomputing, clustered database, and n-tier application serving. They are not–even with VMware, Virtual Server, or Xen hypervisors that would allow workloads to be mixed on the machines–designed to support databases and applications simultaneously because they do not have enough room to add storage (just like the DL320 from HP is too skinny, too). Having said that, if you want to add external arrays and get a baby rack for these HP and Sun machines, you could build a pretty powerful setup.
The last thing I want to point out: I did not create Unix boxes for these comparisons. Unix just isn’t prevalent down in this part of the market, just like Linux really isn’t. If Linux on X64 is rare, you can bet that RISC/Unix is getting even more rare, particularly with Windows being the default platform for SMB customers these days.
Next week, I will take a look at the more mainstream i5 520 servers and how they stack up against similar Windows, Linux, and Unix servers. I am dying to know how that will look myself.