AWS Pricing

The current spot pricing in each zone can be viewed at https://aws.amazon.com/ec2/spot/pricing/ and compared with the full price of a reservation here https://aws.amazon.com/ec2/pricing/on-demand/. While these enable an estimate of the upper and lower bounds of a calculation, we found that the actual price varied a lot, often unpredictably (Table 2).

CPU is generally the largest cost of working in the cloud, but other charges can still contribute. These include the cost of persistent storage in S3 buckets, data transfer between various availability zones in AWS, and egress charges to download data. Uploading data to AWS is free. A detailed breakdown of these costs, with all the complexities of volume-based discounts, zone-based costs, and differential pricing for transfer among zones, is too complex to describe fully here and is covered in detail on the AWS website, but some generalizations are possible. In our experience, data transfer between zones can be up to 4% of the CPU cost and can be nearly zero if work is confined to a single zone. Storage costs in S3 were 1–2% of the CPU cost but can persist over time with additional charges if the data are not deleted after use. Cloudwatch costs, the cost of monitoring jobs with real-time information, cost us 0.5% of the CPU cost, but only because we were watching so closely as we wrote this paper. These charges could be almost zero if monitoring is limited. Obviously, these ratios depend on usage details. Data transfer between us-east-1 and us-east-2 is 1 cent per GB. Between us-east and us-west, the cost is 2 cents per GB. Transferring data between Europe and North America costs the same, just 2 cents per GB, but to and from South America costs 14 cents per GB. These ballpark figures are subject to volume and other discounts. S3 storage is available in tiers. We recommend the usage of “intelligent tiering” which attempts to automatically optimize storage costs and performance and costs 2.3 cents per GB per month. Long-term storage “Glacier” can cost as little as 0.36 cents per GB per month. There are many options and an entire industry focused around optimizing AWS costs.