Bandwidth and CDN pricing not clear

Question

Our servers are located in Europe and most of Azure CDN traffics seems also from Europe. I am curious whether Azure CDN is really necessary for us:

1. we need to pay €0.0737 per GB for the first 10TB Zone 1
2. and we need to pay bandwidth from blob storage to CDN edges.
3. mostly traffic is in Europe

Without using Azure CDN, the bandwidth cost is at €0.0792 per GB for the first 10TB Zone 1.

I am not so sure how to know if moving away from Azure CDN might help reduce the cost but €0.0737 vs €0.0792 does not seem right to me.

FYI. assuming that all assets are compressed with proper caching in place.

Answer 1

@Minh

Welcome to the Microsoft Q&A forum.

Based on your statements above.

Our servers are located in Europe and most of Azure CDN traffics seems also from Europe. I am curious whether Azure CDN is really necessary for us

The major advantages of using a CDN are lower latency and faster delivery of content to users, regardless of their geographical location in relation to the datacenter where the application is hosted. CDNs can also help to reduce load on a web application, because the application does not have to service requests for the content that is hosted in the CDN.

You can consider following recommendations to help you make a more informed decision.

• Perform a load test for your application with and without the CDN and see how the application performances under load. You can refer to Azure Load Testing to help you in this case.
• With CDN out of the picture, the responses will not be cached and it will increase the calls made to your origin. You can take a look at the scale targets for blob storage and validate that the requests are not beyond the targets.

Reference: https://learn.microsoft.com/en-us/azure/architecture/best-practices/cdn#how-and-why-a-cdn-is-used

• and we need to pay bandwidth from blob storage to CDN edges.

As documented here If you are using Azure CDN from Microsoft, the cost of data transfer from Origins hosted in Azure to CDN PoPs is free of charge. Azure Storage service is eligible for free data transfer with Azure CDN from Microsoft.

Apart from this if you have any billing related queries you can open a Billing Support ticket with us as it is offered for free to all the customers. You can refer to my response here to create a Billing Support Ticket.

Hope this helps! Please let me know if you have any additional questions. Thank you!

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Answer 2

Hi @ChaitanyaNaykodi-MSFT

Thanks for your answer.

I will definitely test the scenario without using CDN. Without CDN, I thought the response can be cached or am I wrong? https://learn.microsoft.com/en-us/azure/cdn/cdn-manage-expiration-of-blob-content https://dev.to/tidjani/set-cache-control-to-azure-blob-storage-items-12l5

Maybe my question is not clear enough. I am trying to compare using Azure CDN with downloading assets directly from blob storage.

1. If using Azure CDN, we are paying €0.0737 per GB and latency might be not much better because our storage account is located in Europe.
2. Without using Azure CDN, we are paying €0.0792 per GB and a bit higher latency plus read operation costs. Thus it will be much more expensive. How can it be?
3. If we are using another CDN provider outside MS network, the cost will be much much higher because I estimated the data transfer cost is much higher than how it is right now.