@VijayvigneswarSelvakumar-5228 Welcome to Microsoft Q&A forums.
Azure calculates the pricing based on hourly/monthly cost per instance.
In a multi-tenant use case, your application needs to measure the utilization by tenant based on your business logic.
As a best practice, you should have separate instance of Redis cache per tenant to ensure security of user data.
This also allows for scaling each instance as per utilization and calculating the cost separately.
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