Identify any Amazon DynamoDB tables with underutilized write capacity and downsize the provisioned capacity to lower the cost of your monthly AWS bill. The write capacity downsize process should be used in conjunction with DynamoDB Auto Scaling in order to manage the throughput capacity automatically and save costs. Once enabled, DynamoDB Auto Scaling will dynamically adjust provisioned write capacity on your behalf, in response to current traffic patterns (i.e. when the workload decreases, the throughput will also decrease automatically in order to stop paying for unused provisioned capacity). By default, a DynamoDB table write capacity is considered "underutilized" when the number of write capacity units consumed is lower than the number of provisioned write capacity units set for a table over a specified time period.
The AWS CloudWatch metrics used to detect underused DynamoDB write capacity are:
ProvisionedWriteCapacityUnits - the number of provisioned write capacity units for a DynamoDB table (Units: Count).
ConsumedWriteCapacityUnits - the number of write capacity units consumed over the specified time period (Units: Count).
You are being charged for AWS DynamoDB write capacity, regardless whether or not you use the provisioned capacity units for your tables. To avoid unexpected charges on your AWS bill, it is recommended to downsize the provisioned write capacity to the bare minimum and use DynamoDB Auto Scaling to manage the throughput capacity based on workload.
To identify any DynamoDB tables with underutilized write capacity, available in your AWS account, perform the following actions:
To downsize the provisioned write capacity for your underutilized Amazon DynamoDB tables and enable Auto Scaling in order to automate capacity management, perform the following: