- by David Garrels

We're working on updating our power calculator tools so that when you're considering HP disk arrays, you can identify the power trade-offs of selecting different drive types.  Of course, which drive type you choose depends on a lot of different factors - access time requirements, file/block size needs, etc. and your solution architect or channel partner can help you through that.  But power draw is something you should also consider. 

In general, slower spinning drives use less power.  For example**, a 400GB 10K RPM drive pulls ~8 watts while spinning idle.  A 450GB 15K RPM drive pulls ~12 watts.  That's a significant difference that gets multiplied over the number of drives in the cabinet.  An EVA4400 fully loaded with the 10K drive uses ~770 watts for drive power while the same EVA full of 15K drives will use ~1100 watts.

Again, you need to build the system that will support your application and enable your business goals.  As part of that, you may want to consider the power requirements of the drives you select.

We'd be interested in your feedback - is power draw something you think about when configuring your systems?   

**Note: all power measures are estimates and reference drive power only.  Controllers, fans, etc also consume power and need to be calculated in the overall system requirements.  Our updated power calculators on hp.com will include this.