@Will Davies Welcome to Microsoft Q&A, Thank you for posting your query!
For better understanding the issue: May I know which tool have used to test the performance?
- Can you try again using Azure Speed Test and let me know the status ? May I know what exactly are you trying download and how are you trying to download ?
- Are you downloading to different region or out of Azure?
- May I know the size of the VM and the region?
-Can you please elaborate more on your scenario?
This article describes virtual machine (VM) generic performance troubleshooting through monitoring and observing bottlenecks and provides possible remediation for issues that may occur. Besides monitoring, you can also use Perfinsights which can provide a report with best practices recommendations and key bottlenecks around IO/CPU/Memory. Perfinsights is available for both Windows and Linux VM’s in Azure.
If you are trying download/copy the data from Storage account you can use Azcopy ( AzCopy v10, there's a parameter that lets you directly specify a cap on the amount of bandwidth it uses. E.g. --cap-mbps 200 will limit it to a max of 200 Mbps.)or Storage Explorer
You can use Azure Monitor for VM performance metrics calculation
Virtual machine network bandwidth
Hope this helps!
Kindly let us know if the above helps or you need further assistance on this issue.
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