Ultra slow download speeds from any service that uses Azure.

@Isaac Cajiao Valle Welcome to Microsoft Q&A Forum, Thank you for posting your query here!

There is no throttling on the Azure side, refer to below article. If the network and client machine can handle the traffic then we will send it.

Here's a guide for troubleshooting high E2E latency:

This article lists common problems related to Azure file share performance, and provides potential causes and workarounds: https://learn.microsoft.com/en-us/troubleshoot/azure/azure-storage/files-troubleshoot-performance?tabs=windows

Azure File provide a best IO performance to all users accessing the server with high-importance to data integrity and fairness to all users in all scenarios.
If you are facing any issue in downloading or uploading use azcopy tool.

Is Azure File Share connected via Private Endpoint to your Azure environment like described in this graphic?

https://learn.microsoft.com/en-us/azure/architecture/hybrid/azure-files-private#architecture

Or if your Azure File Share is not using a private endpoint the access might be over your internet connection and not via Express Route.

Performance tuning for file servers

Can you download PerfInsights tool, for Performance data collection Windows
Using PerfInsights:

• Execute PerfInsights using the Azure Files scenario: PerfInsights.exe /r azurefiles /sr 9971**9
• Select Y to agree to share diagnostic information
• Select Y to agree PerfInsights EULA.
• Reproduce the performance issue or make sure that it's occurring.
• When enough data is collected , press any key to stop diagnostic data collection.
• Retrieve the compressed file created under the current folder with format similar to "CollectedData_YYYY-MM-DD_HH-MM-FFF.zip"

You might see slow performance when you try to transfer files to the Azure File service.

If you don't have a specific minimum I/O size requirement, we recommend that you use 1 MiB as the I/O size for optimal performance.

If you know the final size of a file that you are extending with writes, and your software doesn't have compatibility problems when the unwritten tail on the file contains zeros, then set the file size in advance instead of making every write an extending write.

For testing purpose can you use Azcopy tools and check the speed and let me know the status. For transferring Files I would recommend to use AzCopy and File Storage for any transfer files(upload and download). In Azcopy throughput from a single instance will scale at least 20Gbps

Additional information: Sometimes your proxies/VMs or whatever runs in the same datacenter, network requests does not leave the local network and the speed then depends on the infrastructure. (routers, firewalls, cables, etc). I'm sure they won't limit speed between their own infrastructure so services hosted on the same network works at full speed.

Note: Windows OS/Windows Explorer is configured by default, it uses a 4K block size that will produce slower speeds for SMB compared to AzCopy/Storage Explorer which uses REST API.

If the issue still persist, I would recommend you to contact support, so If you have a support plan, I request you file a support ticket, else please do let us know, we will try and help you get a one-time free technical support. In this case, could you send an email to AzCommunity[at]Microsoft[dot]com referencing this thread as well as your subscription ID. Please mention "ATTN subm" in the subject field. Thank you for your cooperation on this matter and look forward to your reply.

Please let us know if you have any further queries. I’m happy to assist you further.

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Hi,

I will suggest you to raise a product feedback over here - https://feedback.azure.com/d365community/forum/8ae9bf04-8326-ec11-b6e6-000d3a4f0789

also you can raise a support case with Microsoft to carry out a detailed investigation - https://azure.microsoft.com/en-ca/support/create-ticket/

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Please Accept the answer if the information helped you. This will help us and others in the community as well.

I have the exact same issue with the same ISP Adamo AS35699 . The connection is via my ISP who have a direct peering with Microsoft in Espanix exchange. I can reproduce the issue with any file hosted in Azure (without CDN) and I also have a personal Azure subscription for testing purposes, however I do not have a support plan purchased. Another example is any content hosted in adoption.microsoft.com have the same slow speed such as https://adoption.microsoft.com/files/sharepoint/SharePoint-Adoption-Playbook.pptx Thanks