Cloud pricing comparison is often an exercise in comparing apples to oranges. Cloud Spectator, an Infrastructure-as-a-Service consulting and research firm, has published a cloud vendor report that attempts to take a nuanced look at the IaaS market and find each provider’s advantage depending on use case.
Comparing on price alone is difficult and can be short-sighted. It’s easy to boil cloud down to pricing, given the regular price cut announcements by the big providers, but lots of other factors are involved.
Other recent efforts at benchmarking the IaaS market include 451 Research’s attempt to create a standard metric and a cloud pricing benchmark in November, and CloudHarmony's report on cloud uptime, which said Amazon Web Services was one of the most reliable providers.
The Cloud Spectator report doesn’t declare a single winner, but where each cloud holds an advantage in terms of contract length or instance size. It covers only 10 vendors and doesn't take performance into account, but provides a good jumping-off point for customers and for Cloud Spectator to delve deeper, which it said it plans to do.
"General pricing comparisons for cloud infrastructure are incredibly difficult because of the number of variables involved,” said Cloud Spectator analyst Anne Liu. “For example, different users will have different configuration requirements, IOPS usage, customer support needs, and desired data locations. Certain features may be included on some providers or cost extra on others. Users looking for a more personalized pricing comparison should take those factors into consideration."
Cost Depends Greatly on Usage
The report found that DigitalOcean, a rapidly growing IaaS startup, Microsoft Azure, and IBM SoftLayer provided the lowest cloud pricing overall, but Amazon’s EC2 displays cost advantages in the longer term when reserved instances are employed. SoftLayer is the least expensive for larger Windows-based offerings over terms of different length.
The most expensive block storage offerings are Rackspace’s SSD and CenturyLink’s Premium block storage, however both are premium offerings focused on performance rather than cost. Azure block storage was the most inexpensive and employs a non-linear pricing model.
There are a few caveats that would potentially change the results. Pricing examined reflects only U.S. data centers. Four separate server configurations were used to compare and contrast each cloud. These configurations were treated as minimum requirements, so the picture gets foggier outside of those selected configurations.
Often, cost comes down to the pricing structure employed by a given cloud provider. Different providers employ everything from pricing for usage under one hour to three-year commitments. The report said Google, Microsoft, and Rackspace excelled in sub-hour subscriptions. Several other providers turned out more cost effective with volume pricing and long-term discounts.
The Other Big Factors
The report also compares service level agreements and reimbursement, geographic availability, and configurability. Amazon, Microsoft, and Verizon are the only three available in all four regions (South America the only missing option in three other clouds).
The bare metal offerings excel at configurability, with CenturyLink listed as the only fully configurable option.
Cloud pricing, feature sets, and data center locations are not static. Providers also continue to retool billing models. AWS recently tweaked its reserved instance pricing model, and Google changed its sustained use discount schema. Amazon's EC2 alone changed prices 44 times since 2006, according to the report.
Cloud Spectator said it is now turning to performance and price performance analysis, with a report expected in a few months.
"Although price is extremely important when comparing providers, it is only part of the story,” said Liu. “Therefore, part two of this report series will incorporate performance to show the price-performance value for each instance. Since an application may require less infrastructure on high-performance providers, this can have a substantial impact on overall cost that cannot be captured with only a price comparison."
Comparison of the big ten is available here (registration required).