Michael S (already5chosen@yahoo.com) on 8/19/08 wrote:
---------------------------
>In the middle of Olympic games
>TPC-C
>IBM System x3950 M2, 8S/48C/48T, Intel Xeon X7460, 2.66GHz, RHEL 5.2, DB2 ESE 9.5,
>512 GB, 1931 HDs - 1,200,632 tpmC at 1.99 $/tpmC


Interesting. First x86 tpmC over one million.

Looking over the disclosure report brings up an interesting issue: despite using (1920) 73GB disks, there's still a space overcommit of something like 2.5-to-1 for the database portion of the disk storage (the rest of this ignores the separate log storage). IOW, there are 2.5 times as many disks as the needed storage for the benchmark requires, strictly to increase the number of actuators (and the available IOPS).

The disk for this submission is about 81% of the total cost (the server itself is about 17%).

That has to lead one to wonder just how far we are from seeing someone submit a SSD based tpmC benchmark.

While SSD is still pretty pricey (about $400/GB for installed enterprise class storage), the reduction in net required storage puts the basic cost at about $19M. Which is, of course a fair chunk higher than the $1.47M of disk on this system.

Now database tables usually compress fairly well, especially fairly synthetic ones, so let's say 3:1 is possible, which drops the SSD storage price to a little over $6M. Compression is usually bad for performance because it increases fragmentation and the number of small I/Os necessary, but that's just the thing SSD excels at. Adding compression will clearly require more CPU, which I'm assuming will happen at the server, but the net is not going to be that much of an increase. Total I/O to the database disk is on the order of a few* GB/s, compressing that much won't take *that* much additional CPU. But let's say it bumps the $300K server by 50%.

That leads to a increase in hardware cost for those components from about $1.8M to $6.5M. While that will lead to a marginal $/tmpC score, it's not that far out of line.

Looking forward, the disk storage needed to support 1.2M tpmC is *not* going to get any cheaper (they're already using 73GB SAS disks - basically the smallest available), but certainly the SSD will. A factor of four in price, and the SSD based system becomes competitive in $/tpmC at the 1.2M tpmC level.

And a question is whether or not enterprise class SSD is really the correct benchmark here. After all, the disk system on this server is using midrange arrays and SAS, not FC, disks. IBM lists (semi reasonably) the 73GB disk at $329***/each, and you can buy “enterprise” 64GB SATA SSD drives off the shelf for $1350**. These out to be basically a straight swap into the array, perhaps with a software/firmware upgrade to handle the SATA disks. Swapping the 73GB drives for .46 times as many 64GB SSD drives (remember the 2.5 times overcommit), and assuming 54% fewer chassis, controllers, etc., ends up costing about $1.56M at the above prices, vs. the $1.44M for the current components. And that would be without any compression. And I’m guessing you’d get something of a discount if you ordered 900 64GB SSDs.

Actual SAS (as opposed to SATA) SSDs will be a bit more, but that’s basically a software change in the drive. And that’s not going to produce much of a performance change. Assuming maintenance charges are basically related to the base price, that leads to an increase in $/tpm/C from $1.99 to $2.11. Which is basically competitive right now, and in a system that will require rather less tuning to get to run at that speed.

Assuming IBM supplied SSD would get a 50% premium like the disks, you’re talking an extra $760K, which kicks the $/tpmC to $2.73.

But both of those numbers suggest that a TPC-C submission in the 1M tpm/C range based on SSD storage for the database should occur in the next year.


*The server in question is configured with eight dual channel 4Gb FC HBAs, which has a maximum theoretical throughput of 12.8GB/s, and the actual sustained rate is going to be rather less than that.

**Imation Pro 7000s in that size are showing 1-3 day delivery for $1320 at CDW, for example.

***Street prices in single units are about $220 (of course that’s without the official IBM stamp of approval).