| Such savings are significant especially when balanced over the lifecycle of the server. However the current costs make this a decision that cannot yet be based solely on the cost savings. For example, if you are paying around 15p per kWh then a saving of 20W per server over a 3 year period would equate to a saving of £78.84. Even if you double that amount due to the power savings of not having to cool the drives, you are still looking at around just £157.68 per server.
That sum is still less than the cost difference today, between traditional hard drives and SSD. However, that premium is continuing to fall and will continue to reduce as SSD approach commodity pricing in the next 12-24 months. This is the time most SSD vendors believe it will take to get manufacturing capacity online, and for the industry to adopt SSD as a mainstream storage technology.
But it is not just about the cost savings in servers. Every datacentre has large arrays of drives storing data. The type of data and the applications that create and consume it differ widely. We already use different storage technologies to deal with the different applications. With thousands of drives already running 24 x 7 x 365, reducing the power by up to 10W per drive is extremely attractive.
Unlike server arrays, storage arrays have a much longer shelf life. They can be in use for up to five years, which is the length of the manufacturers warranty. However, SSD are more resilient and could easily last a decade. This means that the extra cost of SSD when offset against the power saving over that period, makes them an affordable investment today.
Datacentre costs are not just about power and cooling. As the amount of power available to the datacentre continues to be restricted, while the demand for more compute power and storage continue to rocket upwards, there is a need to modify one to accommodate the other.
This is where SSD, especially in storage arrays, has a distinct advantage. There is no longer any need to make the SSD look like a hard drive. The current design assumes spinning disks and moving parts. With no need for moving parts, the only design limitations are fitting inside the enclosure, the data connection and the power connection. These latter two are defined by industry standards. But with no heat to dissipate, a 3U storage enclosure could conceivably hold many more times the number of drives than an enclosure today.
The massive reduction of power from moving away from hard drives to SSD – and the increased density – means that power and space are made available for servers and other components. For the datacentre, this means room to grow, instead of the need to invest in a new building and the migration of the datacentre.
While other savings can be measured in the hundreds, thousands and tens of thousands of pounds, not having to build a new datacentre and migrate systems is a saving that runs into the millions of pounds, most of it CapEx. |