While testing our storage virtualization solution for a client we found interesting situation:
- When object is downloaded directly from Azure Blob Storage to outside of Azure - the speed (tested by wget) is around 0.2 to 0.5 MB/s
- When the same object is downloaded to a VM in Azure - the speed is around 60 MB/s
It may seem like a network issue, but....
- When the same object is downloaded via our proxy that also runs in the same Azure region and actually downloads the same object from Azure Blob Storage without any caching (and converts to S3 which is irrelevant here) - the speed is 30 MB/s and is basically limited by client's network.
I tried different regions and the results are similar.
Is Azure somehow throttles traffic coming from Blob storage to outside of Azure?