In an e-mail to customers today Amazon Web Services announced a new pricing structure for its Reserve Instances service. The pricing will now include three tiers based on usage – light, medium and heavy utilization. The Reserved Instances let you keep machines ready in the cloud but avoid an hourly fee when they’re not running. Previously there was only one pricing tier. You can find information about the new pricing on the Reserved Instances site.

According to the e-mail:

* Light Utilization RIs – Light Utilization RIs offer the lowest upfront payment of all of the Reserved Instance types. Along with this low upfront payment, you’ll receive a significantly discounted hourly usage fee. Light Utilization RIs allow you to turn off your instance at any point and not pay the hourly fee. Light Utilization RIs are ideal for periodic workloads that only run a couple of hours a day, a few days per week, or very sporadically (like Disaster Recovery where they hardly ever are needed, but when they are, you must be sure you have the reserved capacity to handle). Using Light Utilization RIs, you can save up to 28% for a 1-year term and 34% for a 3-year term vs. running On-Demand Instances. If you’re trying to find a break-even utilization, you’re economically advantaged using Light Utilization RIs (vs. On-Demand Instances) if you plan to use your instance more than 32% of a 1-year term or 17% of a 3-year term.

* Medium Utilization RIs – Medium Utilization RIs have a higher upfront payment than Light Utilization RIs, but a much lower hourly usage fee. Medium Utilization RIs allow you to turn off your instance at any point and not pay the hourly fee. Medium Utilization RIs are best suited for workloads that run most of the time, but have some variability in usage (like web server traffic where demand may increase or decrease throughout the year). Using Medium Utilization RIs, you can save up to 34% for a 1-year term and 49% for a 3-year term vs. running On-Demand Instances. If you’re trying to find a break-even utilization, you’re economically advantaged using Medium Utilization RIs (vs. On-Demand Instances) if you plan to use your instance more than 49% of a 1-year term or 24% of a 3-year term.

* Heavy Utilization RIs – Heavy Utilization RIs offer the most absolute savings of any Reserved Instance type. They’re most appropriate for steady-state workloads where you’re willing to commit to always running these instances in exchange for our lowest hourly usage fee. With this RI, you pay a little higher upfront payment than Medium Utilization RIs, a significantly lower hourly usage fee, and you’re charged that lower hourly rate for every hour in the Reserved Instance term you purchase. Using Heavy Utilization RIs, you can save up to 41% for a 1-year term and 58% for a 3-year term vs. running On-Demand Instances. If you’re trying to find a break-even utilization, you’re economically advantaged using Heavy Utilization RIs (vs. On-Demand Instances) if you plan to use your instance more than 85% of a 1-year term or 79% of a 3-year term.

The one time pricing will depend on the size of the instance, the amount of memory and CPU, etc.

AWS is already one of the cheapest options for infrastructure-as-a-service, and the addition of new pricing options is always nice. But the real obstacle AWS faces is providing adequate support and management tools.