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Ars Technica is carrying an interview with Russ Daniels, HP's CTO and VP of Cloud Services Strategy. He discusses a practical definition for cloud computing and distinguishes it from utility computing.
Part 1
Part 2
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We've been interested in applying power-aware techniques to virtualized compute grids, including so-called "cloud computing" grids. A key part of this work is dynamically scaling the amount of compute capacity based on load, which in some cases can be done automatically.
This article presents an opposing viewpoint and points out some ways in which automatically-driven dynamic resizing of compute resources might be a bad thing. I think the author goes a bit to far in throwing out automatic scaling entirely, but he does raise several valid points, especially with respect to security and the possibility of DDOS attacks.
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I found an article that shows interesting analysis of power savings in a data center. In a 5,000-square-foot data center, a 1-watt reduction at the server-component level (processor, memory, hard disk, etc.) results in an additional 1.84-watt savings in the power supply, power distribution system, UPS system, cooling system, etc. Consequently, every watt of savings that can be achieved on the processor level creates approximately 2.84 watts of savings for the overall facility.
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Tom's Hardware tested the power and performance of current Solid State Disks (SSDs) both in terms of performance and power. While the performance numbers were as expected, it turns out that the flash based drives' energy utilization is no better than a traditional 7200 RPM hard disk for a practical workload based on the MobileMark benchmark. The authors contend that this is because hard disks reach their maximum power draw only when seeking, whereas flash storage uses full power during any IO activity.
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The Barcelona (aka "K10") microarchitecture is the latest design from AMD for both the server and desktop markets. The Phenom is the quad-core desktop variant, the Athlon X2 series includes the dual-core variant, and the 23xx and 83xx Opterons are the quad-core server varient.
The key changes over the previous line are covered in brief here and in greater detail here. Most of the interesting features require the use of an upgraded CPU socket denoted by a "+" (e.g. Socket AM2+ or Socket F+), though the CPU will work in non-plus sockets on current motherboards. Some of the "plus socket" features are:
• Separated voltage planes allow the CPU to have a different voltage/frequency for each core and the northbridge.
• HyperTransport 3.0, allowing greater bus bandwidth, including support for DDR2-1066.
In addition, the Barcelona introduces a shared L3 cache, which should have a major impact on HPC applications.
One major issue, however, is an L3 TLB bug present in the first generation of this architecture. This problem can be solved by disabling part of the L3 TLB system in the BIOS or via software (with a 10% performance penalty), or using a unique Linux patch to route around the problem with limited slowdown (but the patch is not intended for production use). See the Phenom wikipedia article for details.
In short, while Intel retains the upper hand in horsepower now, the AMD Barcelona design seems to sport many of the features predicted for future system design.
More information:
Wikipedia's Barcelona article covers the architecture in depth.
Anandtech benchmarking puts the chip through its paces.
To find a Barcelona-based chip, see Wikipedia:
• Phenom quad-cores
• Barcelona-based dual-core Athlons (scroll to "Phenom based")
• Barcelona-based quad-core Opterons (23xx and 83xx)
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This recent "Innovations" article highlights "utility computing", the idea that virtualization, shared storage, and other technologies will come together to commoditize business computing.
While I agree with the general idea, the author predicts that this will marginalize IT as a field, which seems counter-intuitive. While this kind of computing does allow fewer people to manage more systems, it does make that management that much more complicated. Further, IT has always been about helping users as much as maintaining infrastructure. So I don't see the general IT realm getting eaten by other fields, but rather splintering into specialists in networking, storage, (virtual) system administration, support, etc.
Finally, I found this quote pretty funny:
Teenagers entering higher education today are already skilled at building personal application spaces on Facebook using software modules. It’s a small step to apply those principles to business applications.
"A small step" to go from facebook to a crucial business application? Seems unlikely.
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The article explains the difference in detail. Now, I can understand why it's too difficult to run Java Web server on OpenVZ for evaluating TPCW benchmarks.
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There is some good information about adaptive power management at Berkeley. It appears to be a position statement/paper in construction arguing for power management in data centers.
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By way of slashdot, we find that the Linux kernel (2.6.23 and up) now sports three virtualization techniques out-of-box: KVM, Xen (just merged), and Lguest (also recently merged).
Lguest in particular looks interesting, as it doesn't require virtualization hardware support (like KVM), but is as simple as a single modprobe (as opposed to the Xen behemoth). Performance isn't too great right now, though (-30%).
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