Going Green

I was touring a datacenter at a customer recently and walked into a huge room that was maybe 1/8th full. The IT manager noted that this datacenter was now “at capacity” and no more systems could be added. He commented that the industry has been so good at increasing the power density that most of the existing data centers now run out of power when the are only 25% “full.” Today, new data centers are being built with 3 to 4 times the power and cooling capacity of existing facilities. They are also being built in locations that can be better served with massive amounts of power (e.g. near big power plants) because it is easier to move bits (data) than atoms (power).

To put it bluntly, green computing is not a fad; it is a pervasive trend based on simple economics. The economic reality is simple; the cost of power is now a major driver of datacenter operational costs. 

Storage systems are a big power consumers and, unfortunately, they have gotten exponentially worse as we have increased the speed of disk drives. Unfortunately, when we increase the rotational speed of a disk, power consumption increases exponentially. Basically, doubling disk performance (in terms of rotational speed) effectively quadruples power consumption – not a good thing.

Green Technology

While we will always work to make systems more efficient in terms of power consumption, I believe the big gains will come from several specific technologies. 

The most obvious of these is virtualization. Virtualization has enabled dramatic server/application consolidation. Going forward, with even better tools to enable dynamic load management, we will truly be able to dynamically power off and on server capacity. For the few people that haven’t networked and separated severs and storage, your costs will continue to rise as virtualization simply will not be effective.

Information Storage is a completely different animal. Information (capacity) does not grow and shrink with load and it is difficult if not impossible to completely “turn off” access to information. Much can be done however by using new techniques and technologies that can dramatically reduce the power load and still insure access performance and availability. 

One of the new trends will be the use of high-reliability flash to create a new high-performance/low power storage tier – "Tier 0" as it is often called. This is not the flash in your iPod (which has a life of maybe 10,000 writes); it has much higher cycle life, making it practical for enterprise storage applications.  Flash of this type is not cheap but it can have a great ROI for frequently accessed information, especially when the power costs are considered.

Another trend will be the increased use of bulk storage tiers that leverage high capacity medium-performance drives. In many cases the drives will be spun down when not in use. Access will be slower but it will still only take “seconds” to get the information. In many cases, such as with archives, this will be more than sufficient.

I am often asked if we will now store more data “offline” on tapes, DVD’s,etc. My simple answer is no. The cost of manually managing physical media and long access times make these repositories impractical. 

So, while technologies like virtualization, flash, and even information lifecycle management (storage tiering) were not invented specifically for energy conservation, they are clearly being adapted to address this need. We (the IT industry) are fortunate because I believe this will be one of the key areas of IT investment for 2008.





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