Slow file copying to and from Azure file shares

Theodoros Yiorkas 25 Reputation points

I am a new user of Azure Files and I am trying to transfer my organization's data to Azure Files and I noticed that the file copy speed is extremely slow, below 1MB/s. Although I know that using AzCopy or RoboCopy will be more efficient in terms of migration, I am hesitant to move to our production environment as I don't want our employees to experience slow speeds. Are there any methods to increase the file copy speed to and from Azure File shares?

Azure Files
Azure Files
An Azure service that offers file shares in the cloud.
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  1. Carlos Solís Salazar 17,351 Reputation points MVP


    First, I would recommend you check your company's Internet bandwind.

    Also, you can customize your azcopy command, please check this document.

    You can increase the number of concurrent requests:

    You can increase throughput by setting the AZCOPY_CONCURRENCY_VALUE environment variable. This variable specifies the number of concurrent requests that can occur.

    I hope this helps!

    Remember to accept the answer if it is helpful.

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  2. Nehruji R 3,651 Reputation points Microsoft Vendor

    Hello Theodoros Yiorkas,

    Greetings! Welcome to Microsoft Q&A Platform.

    There are several reasons why the download speed from Azure File Share may be slow. Here are a few possible causes:

    Network conditions: The speed of the file download can be affected by the quality of your internet connection and the distance between your computer and the Azure datacenter where the file is stored.

    File size: The larger the file size, the longer it will take to download.

    Concurrent connections: If multiple users are accessing the same file at the same time, it can slow down the download speed for each user.

    Azure File Share performance tier: The performance tier of the Azure File Share can also affect the download speed. If you have a standard-tier storage account, the download speed may be slower compared to a premium-tier storage account.

    To increase the download speed, you can try the following:

    Use a wired Ethernet connection instead of WiFi to improve the stability and speed of your internet connection.

    Increase the bandwidth of your internet connection if possible.

    If you are downloading a large file, try downloading it in smaller chunks using a tool like wget or aria2c.

    If you are accessing the file from a virtual machine (VM) in Azure, you can try attaching a Premium SSD or Ultra Disk to the VM to increase the read performance.

    If using a standard tier storage account, consider upgrading to a premium one to improve performance.

    This article lists some common problems related to Azure file shares. It provides potential causes and workarounds for when you encounter these problems. Azure file shares performance issues,

    You can use Azure speed test tool to check the speed:

    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.

    Hope this answer helps! Please let us know if you have any further queries. I’m happy to assist you further.

    Please "Accept the answer” and “up-vote” wherever the information provided helps you, this can be beneficial to other community members.

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