I'm using direct SMB 3.0 connection (no proxy/vpn in between) to Azure Files from on-prem. The read speed is OK (about 25MB/s) but the write speed is very slow (about 3-5MB/s).
I tried direct SMB 3.0 connection to the same Azure Files share from an Azure VM in the same region, then the read speed is about 130MB/s, but the write speed is slower (about 30-40MB/s).
I understand that the number in Azure VM is higher due to lower network latency. But it looks write speed is always considerably slower comparing to read speed.
If I setup a file share on my own within my network, I can get read/write both about 100MB/s, so this is not a native SMB behavior. Is there something special about Azure Files so that write speed is slower? Is there some parameters I can tweak on my side to improve that? Thanks!
------------- Update on Mar 8 -----------------
Some update about the details.
1. I'm trying to use SMB protocol (map network drive on Windows Explorer), not uploading from Azure Portal
2. To eliminate potential impact from other software, I created a fresh new Azure VM (Windows 10 ver 2004) in East US datacenter and an Azure Files share in West US datacenter (to simulate the latency between my on-prem server and Azure Files). I was able to reproduce the issue, please see the pictures below:
Write speed: less than 1MB/s
Read speed about 17MB/s
BTW, I also tested upload from Azure Portal, the speed was slow too (less than 1MB/s). Tried AzCopy too, but it seems cannot upload to Azure Files (only to blob storage)