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David Reinsel, group VP of the storage and semiconductor research groups at Framingham, MA-based IDC, says IT customers haven't reached the point where they're willing to pay money just to get a green, eco-friendly stamp of approval on hardware and software. "In today's economy, even with the price of energy going up, spending is very conservative when it comes to energy conservation," says Reinsel.
Daffan bought Xiotech systems built on the company's Intelligent Storage Element (ISE) technology (which, in turn, is built on technology Xiotech acquired from Seagate last year). Daffan evaluated seven storage vendors and compared them based on throughput associated with large, sequential reads and writes, as well as the ability to accommodate more than 200TB of data in coming years. He also compared power specs and requirements from all of the competing vendors.
With the price of power fluctuating widely and his usage requirements rapidly growing, Daffan says making a multiyear analysis of power costs among different products based on vendor specs without in-house testing wouldn't be an accurate or meaningful exercise. When it came to performance metrics, he says, the ROI was simple. "On our previous system, we had four hosts attached to the SAN and our CPU utilization was about 20% to 25%. It basically came down to the fact that we just couldn't get data off the disk fast enough to
| feed the CPU. At the time, we were about 200MB per second spread across four hosts," says Daffan. Now, he says, the CPU utilization on the hosts is up approximately 70% to 75%. "We're getting 600MB to 800MB of throughput per host. We are pushing over 2GB per second," says Daffan.
Tim Hershberger, Xiotech's product manager, says there are plenty of meaningless metrics on how to determine how "green" a product is. "Which rack of equipment is taking the most power to do something is totally irrelevant," he says. The trick is to take real-life workloads comparing "apple-to-apple examples of how many dollars you're spending per IOPS. Basically, the metric looks like this: Given an equal workload, what's the power consumption of watts per enclosure per IOPS per disk?" he says.
Some storage administrators are starting to plug storage vendor-supplied product power numbers into so-called green calculators, says Wayne Adams, chair emeritus of the Storage Networking Industry Association (SNIA), as well as senior technologist and director of standards, office of the CTO at EMC (see "The green calculator," below). The challenge, he says, is obvious. "[The numbers are] not audited by anyone; the only way to know if they're right for you is to go out and purchase the equipment and test it. I don't think any vendor is being dishonest," says Adams. "[But] there may be inconsistencies to each vendor's response to the power calculator."
This was first published in October 2008