Denys Rudyi - Fotolia

Solid-state drive costs: What factors do I need to consider?

SSD costs are on the downswing, but users need to explore the price per IOPS and price per gigabyte before purchasing. Some workloads aren't a match with the technology.

It isn't exactly an industry secret solid-state drive costs are plummeting. Not that long ago, $1 per gigabyte was considered the price point at which mainstream adoption of SSDs would begin at the enterprise level. While solid-state drive costs vary widely based on factors such as manufacturer, capacity and NAND type, there are drives that cost less than 35 cents per gigabyte. Technologies such as triple-level cell -- which decreases the cost per gigabyte by cramming more data onto each cell, thereby increasing capacity -- have also contributed to falling price points.

When performing a cost-benefit analysis of SSD and HDD media, organizations usually look at two factors: price per IOPS and price per gigabyte.

SSDs are almost always the better choice for IOPS-intensive workloads, especially when those IOPS are random. There are some high-end HDDs on the market that can perform linear IOPS at a rate that is somewhat comparable to solid-state drives, but SSDs offer superior performance when it comes to random IOPS.

Because solid-state drive costs are higher than those for HDDs, some organizations estimate the number of IOPS required by their workloads and then create large arrays of commodity HDDs. By striping data across large numbers of HDDs, data storage administrators can achieve IOPS levels approaching those of SSDs. But there are disadvantages to this technique:

  • The cost of the necessary disk controllers, since a large number of disks may be required.
  • Wasted storage capacity, because there is a good chance the organization will not need the full capacity of the HDDs that have been striped together.

Workloads that generate large volumes of random IOPS -- such as databases, hosting a collection of virtual servers and video production -- will benefit the most from solid-state drive adoption and falling solid-state drive costs. Workloads in which the majority of the server's activity occurs in memory, rather than on disk, would benefit the least from SSD technology. For example, a DNS server probably would not receive much benefit from SSD storage, because it isn't an IOPS-intensive workload.

Next Steps

How to ensure performance of IOPS in the data center

Judging the performance of SSDs

For all-flash storage arrays, price per gigabyte is not the only consideration

Transition in data centers triggered by growth of SSD storage array

Dig Deeper on Solid-state storage