"Green" DataCenters

My co-worker recently returned from Storage Decisions in New York City. Many of the presentations focused on the concept of the "green" data center, and how server/storage products were adapting to those initiatives. Many believe that by retooling servers, storage and network devices to be more power/cooling friendly, it will benefit the bottom line - cost savings, environmental impact and so forth.

In practice, however, few of these savings are realized, yet more companies jump on the bandwagon. In regards to storage, several vendors announced products at SD2007 to follow these initiatives. Some vendors have implemented storage arrays that spin down drives when not in use. Others have implemented high-efficiency power supplies, to reduce electrical loss and waste heat generation. A few have even gone so far to offer tools to allow admins to control power consumption - giving users direct access to "power profile" configurations recently introduced in Seagate and Hitachi hard disks.

What does this mean for administrators? Nothing good, in my opinion. Hard disks are only guaranteed to tell you they're not working when there is power applied to the drive. When a hard disk spins down, there is no guaranteed method to a) ensure the drive will spin up or b) report that a drive will not spin up reliably. If there's anything the Google disk failure report indicates is that silent failures are both possible and probable. SMART reporting from drives was not possible with 100% of spinning, active drives - spinning down a drive, which turns off SMART, certainly won't improve failure prediction rates. Administrators will now be faced with many more disk failures and higher replacement costs, reducing any cost savings realized.

What does this mean for end users? Nothing good, either. Users will now see even more delays as arrays spin up data drives, in response to data queries. Delays access web images on shopping sites results in customers looking elsewhere.

What does this mean for manufacturers? More money. Including a license to control green features on an array is a sure-fired cash cow. As most of the spin-up/spin-down command infrastructure is already present in the SCSI command set (UNIT_OFFLINE, UNIT_ATTEN, etc.), it was relatively easy to port this functionality into the SATA and SAS command sets. Power supplies with only 10% or 20% efficiency improvements over standard power supplies command 50% premiums in the open market. Vendors can inflate this cost to more than double, realizing considerable profit.

In my estimation, green data centers don't offer anything today. Another generation of product advances (specifically in the power supply and heat dissipation areas) are necessary to realize any worthwhile cost-savings from green initiatives. Sure, it might make us all feel warm and fuzzy inside, but I can get the same benefit from a nice, wool sweater.