It's time to pay attention to storage power use: Best Practices
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Avoid overspending and overprovisioning.
It's pretty obvious that spinning disk is the source of most storage power consumption, and unused spinning disk represents wasted energy. But there are several challenges in growing storage incrementally. The first relates to the organization's ability to accurately forecast storage capacity needs. Beyond capacity planning, it requires a relationship with a vendor who can support the incremental storage growth. Finally, the technology must be such that storage can be expanded easily and with minimal disruption.
Revisit your tiering strategy.
Small, fast disks demand more energy than large, slow disks, so the distribution of data across various tiers of storage can have a big impact on your power consumption. An EMC Corp. study indicates that storing a terabyte of data on a 7,200 rpm 1TB SATA drive is 94% more efficient than storing it on a 15,000 rpm 73GB Fibre Channel drive.
This provides an added incentive to ensure that storage service levels and their
associated tiers are properly aligned based on application and data value. There are many situations where tiered storage allocations are far from ideally distributed. Understanding this distribution and developing a clearly defined set of service-level requirements to apply to new applications and existing apps can lead to substantial savings in equipment cost and energy use.
Revisit RAID policies.
Another facet of a tiering strategy is the RAID protection policy applied to a given tier of storage. It's not so prevalent these days, but overprovisioning of RAID 1 or RAID 10 increases the number of spindles and power consumption. When additional performance or availability isn't required, drive count can be reduced.
Consolidate storage arrays.
The more frames in a data center, the more power that needs to be reserved for them. In addition, older arrays tend to be less efficient than the latest models. Reducing the number of storage systems is an obvious option, just as consolidating physical servers through virtualization is.
Speaking of virtualization, newer arrays may offer enhanced functionality such as thin provisioning to improve utilization and further reduce energy consumption.
This was first published in November 2008