Analyzing cost savings and usage of your AWS reserved instances

Use the Existing Reserved Instances page to get a quick view of all the active reserved instances, whether shared or dedicated, in your infrastructure across all the accounts. You can also view a summary of the cost savings and usage of your active AWS reserved instances and you can drill down into a specific reserved instance to analyze its specific cost and usage details. You can maximize your cost savings by regularly reviewing and analyzing your reserved instances. 

To access the Existing Reserved Instances page, in the navigation pane of the TrueSight console , select Cloud Cost Control and click Cost Optimization > AWS Reserved Instances, and on the page, click <Number> Existing Reserved Instances.  

From this page, you can achieve the following goals:

• Analyze whether your AWS reserved instances are optimally used or not.
• View details of all the active AWS reserved instances across all your accounts.
• Analyze the total cost savings that you gain by using reserved instances.
• Identify and analyze the reserved instances with low usage.
• Determine the reserved instances that will expire soon.
• View and compare the monthly savings and usage of all the reserved instances in your AWS infrastructure.
• View and compare the breakup of the monthly usage of a reserved instance.
• View line item details of usage of a reserved instance.

Before you begin (Upgrade scenario only)

If you have upgraded to the current version of the product, recover the historical AWS data to evaluate the AWS reserved instance costs. For more information, see Upgrading.

To analyze cost savings and usage of your AWS reserved instances

1. Access the Existing Reserved Instances page
   

   In the navigation pane of the TrueSight console , select Cloud Cost Control and click Cost Optimization > AWS Reserved Instances. On the page, click <Number> Existing Reserved Instances.  
   
   
   The Existing Reserved Instances page provides a quick overview of the number of active reserved instances in your infrastructure, their associated monthly cost savings, your monthly cost savings based on their usage, and a list of the reserved instances and their details. By default, the information for the current month is displayed. Use the global monthly filter to view the reserved instances data for a specific month in the past or the current month.

   Information

   The AWS Reserved Instances page is displayed only if you are using the AWS cloud provider.

   
   

2. Analyze the total cost savings with reserved instances
   

   Review the (A) Reserved Instances Summary and the (B) Reserved Instances table sections to review and obtain a summary of the total monthly savings with reserved instances, and a quick view of each reserved instance.
   
   
   

   A. Reserved Instances Summary section Provides the following information about the active reserved instances in the currently selected month: Count of the active reserved instances in your infrastructure Total Savings (in $) that you achieve based on the discount associated with using the reserved instances. The amount is displayed in Red font when the savings are negative. A negative amount indicates that some or all your reserved instances are not utilized effectively. Total realized savings in a graphical format that enables you to quickly compare the Savings value with that of the Max savings value. For more information about the Savings and Max Savings values, see Calculating the Savings and Max Savings values. Information: The gap or difference between the Savings and Maximum Savings values can be minimized by ensuring that the usage of the reserved instances is high. 100% usage of reserved instances equals maximum savings with reserved instances. You can hover your mouse over the chart to see the specific values. Warning about reserved instances that will expire in the current month or in the following month. Tip Use the warning information to decide whether you must let the reserved instances expire or purchase new ones that match the instance attributes.

   B. Reserved Instances table The table contains a row per reserved instance and provides information such as the reserved instance ID, instance type, start and end date of the reservation, number of instances purchased in the reservation, monthly savings, and percentage of used hours. These values are populated from your detailed AWS billing report. To know the savings for a specific reserved instance, review the Savings column value. A negative amount is highlighted in Red color. The negative amount means that the instances in the reserved instance are not optimally utilized and you are paying for unused resources. The Used Hours column value provides the total percentage of hours that a reserved instance is used.  As shown in the following example, you can review the values in the Savings and Used Hours columns to determine whether a reserved instance is optimally utilized or not. By default, some columns are hidden. For example, Tenancy, Max saving. You can show or hide columns using the action menu that is located next to the table title.

   
   You can drill down into a reserved instance to review and analyze it further. 
   
   

3. Drill down into a reserved instance for detailed usage analysis

   1. In the Reserved Instances table, click the ID of the reserved instance that you want to investigate or view details for.
      The AWS Reserved Instance Details page opens with the Summary page open by default. This page provides a quick view of the savings and usage information for the selected reserved instance. Also, provides other details such as offering class and type, tenancy, start and end date of the reservation, and so on.
      
      Use the Monthly Savings chart to analyze and compare the realized savings amount month-by-month. The chart also enables you to compare the monthly actual savings with the maximum savings to know whether the total realized savings is positive or negative. When you hover your mouse over the bars in the chart, you can see the value in $.
      
      

      Information

      The Savings value can be positive or negative depending on whether you are saving money by using the reserved instance or not.

      Consistent negative values over a period indicate that the reserved instance is not cost-effective and probably you need to opt for on-demand instances to reduce your costs. You can investigate further by analyzing the usage details of the resources.

      
      The following screenshot shows the Reserved Instance Details page. 
      

   2. To view details of all the resources that are reserved, click By Resource. Details such as resource name, usage hours, instance type, and so on, are displayed. 

      Tip

      To drill down into a resource, click the resource name. The Usage details page opens that displays information about the selected resource.

   3. To view specific usage details of all the resources, click the Usage Details tab. The table lists a line-by-line consolidated list of all resources with a usage description of each line item.
      
      

      Tip

      To view usage details for a specific resource, use the Resource filter.

      

4. (Optional) To save an offline copy of the reserved instance details, click Settings and select Export to Excel or Export to PDF.
   
   

Calculating the Savings and Max Savings values

Savings is the difference between the on-demand cost of the instance and the cost of the reserved instance, where the instance type remains the same. It is the cost that you saved by using reserved instances. 

Max Savings is the amount of savings that you can gain by using your reserved instances to its maximum capacity or potential. 

Calculations of these savings is based on the following parameters:

• Number of hours of usage 
• On-demand hourly cost of the instance type 
• Effective hourly pricing of the instance type based on the selected payment option  

Consider the following example to understand how the values for monthly Savings and Max savings are calculated for a reserved instance. 

Total number of hours in a month	= (number of days in a month) x (total hours in a day)
									= 31 x 24
									= 744

On-demand cost of the instance 	= (On-demand hourly cost of t2.2xlarge) x (number of machine hours of usage)
								= 0.5012 x 700
								= $350.84

Cost of the reserved instance 	= (Effective hourly pricing of the instance type) x (Total number of hours in a month) 
								= 0.360 x 744 
								= $267.84

Savings = (On-demand cost of the instance) - (Cost of reserved instance)
		= 350.84 - 267.84
		= $83

On-demand cost of the fully-utilized instance 	= (On-demand hourly cost of the instance type) x (Total number of hours in a month)
												= 0.5012 x 744
												= $372.89

Maximum savings = (On-demand cost of fully-utilized instance) - (Cost of reserved instance)
				= 372.89 - 267.84
				= $105.052