Amazon ElastiCache Reserved Cache Nodes

Amazon ElastiCache Reserved Cache Nodes give you the option to make a low, one-time payment for each cache node you want to reserve and in turn receive a significant discount on the hourly charge for that Cache Node. Amazon ElastiCache provides three ElastiCache Reserved Cache Node types (Light, Medium, and Heavy Utilization Reserved Cache Nodes) that enable you to balance the amount you pay upfront with your effective hourly price. Based on your application workload and the amount of time you plan to run them, Amazon ElastiCache Reserved Cache Nodes may provide substantial savings over running on-demand Cache Nodes.


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Features

  • Reserved Cache Nodes are available in three different types: Light, Medium, and Heavy Utilization.
  • Reserved Cache Nodes can save you up to 70% over On-Demand rates when used in steady state.
  • Reserved Cache Nodes are easy to use and require no change to how you use Amazon ElastiCache. When computing your bill, our system will automatically apply Reserved Cache Node rates first to minimize your costs. A cache node hour will only be charged at the On-Demand rate when the total number of cache nodes you run that hour exceeds the number of applicable Reserved Cache Nodes you own.
  • Reserved Cache Nodes can be purchased for one or three year terms.
  • Reserved Cache Nodes are available in all the AWS regions.

Reserved Cache Node Types

There are three Reserved Cache Node types shown below that enable you to balance the amount you pay upfront with your effective hourly price:

  • Light Utilization Reserved Cache Nodes – – Light Utilization Reserved Cache Nodes offer the lowest upfront payment of all of the reserved types. Along with this low upfront payment, you’ll receive a significantly discounted hourly usage fee. Light Utilization Reserved Cache Nodes allow you to turn off your Cache Node at any point and not pay the hourly fee. Light Utilization Reserved Cache Nodes are ideal for Cache Nodes with sporadic usage. For example, development and test nodes that run for about seven to twelve hours a day or the Cache Nodes used for short term projects and run for 3-7 months in a year. Using Light Utilization Reserved Cache Nodes, you can save up to 42% for a 1-year term and 56% for a 3-year term when compared to running the same cache node on an On-Demand basis.
  • Medium Utilization Reserved Cache Nodes – Medium Utilization Reserved Cache Nodes have a higher upfront payment than Light Utilization Reserved Cache Nodes, but a much lower hourly usage fee. Medium Utilization Reserved Cache Nodes allow you to turn off your Cache Node at any point and not pay the hourly fee. They are best suited for workloads that run most of the time, but have some variability in usage. Using Medium Utilization Reserved Cache Nodes, you can save up to 47% for a 1-year term and 64% for a 3-year term when compared to running the same cache node on an On-Demand basis.
  • Heavy Utilization Reserved Cache Nodes – Heavy Utilization Reserved Cache Nodes offer the most absolute savings of any Reserved Cache Node type. Most production applications require cache servers to be available 24×7. Heavy Utilization Reserved Cache Nodes are most appropriate for your steady-state production workloads that will be always running, so you commit to the entire duration of the Reserved Cache Node term. With this Reserved Cache Node, you pay a higher upfront payment than Medium Utilization Reserved Cache Nodes and the lowest hourly usage fee. You are charged this low hourly rate for every hour in the Reserved Cache Node term you purchase. Using Heavy Utilization Reserved Cache Nodes, you can save up to 52% for a 1-year term and 70% for a 3-year term when compared to running the same Cache Node on an On-Demand basis.

Use Cases

Reserved Cache Nodes are a great option for a number of different use cases.

Steady State Usage

Most production applications require cache nodes to be available 24×7. Reserved Cache Nodes could provide your business substantial savings if you exclusively use On-Demand Cache Nodes for your production applications. Heavy Utilization Reserved Cache Nodes offer the largest discounts for steady state workloads. If you expect your Cache Node to be running most of the time but value the flexibility of being able to turn off your Cache Nodes at any point, Medium Utilization Reserved Cache Nodes may be the right choice for you.

You can determine whether Reserved or On-Demand Cache Nodes best fit your needs by comparing On-Demand hourly rates and the effective hourly rate of Reserved Cache Nodes. In order to calculate an effective hourly rate, amortize the one-time fee over the term and add the hourly usage rate. At steady state usage, the effective hourly rate for 1 year term Heavy Utilization Reserved Cache Node is 52% lower than On-Demand rates and 3 Year term Reserved Cache Nodes are 70% lower. For Medium Utilization Reserved Cache Nodes with steady state usage, 1 year reservations are 47% lower and 3 year Reserved Cache Nodes are 64% lower than corresponding On-Demand rates.

Low to Medium Annual Utilization

Reserved Cache Nodes can also provide significant cost savings even if your cache nodes run less than 100% of the time. Unlike traditional dedicated capacity, Light and Medium Utilization Reserved Cache Nodes allow you to avoid usage charges when you don’t need the node. If your workload requires a cache node to run for 3-7 months in a year (e.g. scaling up the number of cache nodes during peak season for your business), a 1 year term Light Utilization Reserved Cache Node allows you to minimize your ElastiCache bill.

Reserved Cache Nodes Pricing

Light Utilization Reserved Cache Nodes

Medium Utilization Reserved Cache Nodes

Heavy Utilization Reserved Cache Nodes

How Billing Works

Customers using both Reserved and On-Demand Cache Nodes will have Reserved Cache Node rates applied first to minimize costs. Each hour, if the number of running cache nodes is less than or equal to the number of applicable Reserved Cache Nodes you have, all running cache nodes will be charged at the Reserved Cache Node hourly rate. When your total quantity of running cache nodes exceeds the number of applicable Reserved Cache Nodes you own, you will be charged the On-Demand rate.

For example, if you own 3 Reserved Cache Nodes with the same Cache Node type in a given region, the billing system checks each hour to see how many total cache nodes you have running that match those parameters. If it is 3 or less, you will be charged the Reserved Cache Node Rate for each cache node running that hour. If more than 3 are running, you will be charged the On-Demand rate for the additional Cache Nodes.

If you purchase a Reserved Cache Node in a given region where you have a running Cache Node, the lower hourly charge will automatically be applied to that cache node moving forward with no need to restart.

How To Purchase Reserved Cache Nodes

Reserved Cache Nodes can be purchased using the AWS Management Console or API tools.

AWS Management Console:

  1. Log in to the AWS Management Console, click the “Amazon ElastiCache” tab
  2. Select the Region in which you would like to make your Reserved Cache Node purchases
  3. Select “Reserved Cache Nodes” in the navigation pane and click on the “Purchase Reserved Cache Node” button
  4. Select the cache node class and the term length
  5. Adjust the quantity of cache nodes to purchase
  6. Click on “Continue”, verify the purchase information, and confirm

Please refer to Amazon ElastiCache Documentation for information about using the API tools.

Important Notes about Purchases:

  • Region, Cache Node Class, and term length must be chosen at purchase, and cannot be changed later.
  • You can purchase up to 20 Reserved Cache Nodes. If you need additional Reserved Cache Nodes, complete the form found here.
  • The one-time fee is non-refundable.
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