Azure Files
An Azure service that offers file shares in the cloud.
How to fix slow write speeds over SMB for file shares
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Jacob Kluber
0
Reputation points
I have a file share mounted as a network drive and if I copy a 500MB folder within the same file share and paste it into the same place the action takes nearly 2 minutes. The same action done on our mirrored on-premises file server takes only about 10 seconds.
I have tried increasing the access tier to hot and with a premium storage container and in every case the performance remains the same. I have had no success in reducing the latency.
Azure Files
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Nandamuri Pranay Teja 4,610 Reputation points Microsoft External Staff Moderator2025-08-12T20:14:37.7466667+00:00 Hello Jacob Kluber
Thank you for posting the question!
Please be informed that Transferring a 500MB folder within a network share is a time-consuming process, as the files are first downloaded to your computer and subsequently re-uploaded to the same share. When this action is executed on a cloud-based network drive, it is not considered a local operation. Your computer serves as an intermediary, retrieving the data from the cloud storage and then sending it back, which results in significant latency.
However To speed up the process, you should use AzCopy which is a command-line utility designed for high-performance data transfer with Azure Storage.
To investigate further could you please provide me the below details
- What version of Windows are you using for the SMB client?
- Are there any specific network configurations (like VPNs or firewalls) that could be affecting performance?
- What is the performance profile of the storage backing your Azure file share (e.g., IOPS, throughput)?
- Are there any other applications or services running on the same machine that could be affecting performance?
Let me know if you have any questions or concerns. I'm here to help
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Jacob Kluber 0 Reputation points
2025-08-13T13:45:58.8666667+00:00 Hi, AzCopy would be too burdensome for our users who have no technical background and just need to browse files.
- Windows 11 Pro
- We have a firewall and a site-to-site IPsec with a virtual gateway and local gateway in Azure.
- The storage container is standard performance, cool tier, Vpngw1. I did a test recreating the file share in premium tier with 200 TB reserved space with default configs on that and the copy time was about the same.
- Not that I know of
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Nandamuri Pranay Teja 4,610 Reputation points Microsoft External Staff Moderator
2025-08-13T14:27:13.46+00:00 Hello Jacob
Thank you for the additional details
In this case Consider Upgrade VPN Gateway SKU to VpnGw2 (1.25 Gbps) or VpnGw3 (1.25 Gbps with better PPS performance). This often provides dramatic improvement for file operations.
If possible, configure SMB Multichannel on both the Azure Files share and your Windows clients. This can help utilize available bandwidth more efficiently.
Coming to Network Path Optimization check if you can use ExpressRoute instead of site-to-site VPN for better, more consistent performance Ensure your on-premises internet connection isn't the limiting factor.
Let me know if you have any questions If this answers your query, do click "Up-Vote” for the same, which might be beneficial to other community members reading this thread. And, if you have any further queries do let us know.
Else let me know your availability so that we can connect over call to discuss this. I have reached you via private messaging i request you to kindly provide me the details.
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