Windows 11 de Microsoft

Windows 11 and networks, Microsoft speeds up file transfers – GinjFo

Microsoft makes a major change around SMB in Windows 11. It’s the compression feature. It becomes more impressive, which reduces the size of the files and consequently the time needed to transfer the data.

Windows 11 and Windows Servers 2022 take advantage of an SMB compression feature. SMB is short for Server Message Block. It is a communication protocol that allows sharing data and printers. We also find it when browsing networks.

This compression reduces the size of files during a transfer. Avoid manual interventions. There is no need to compress the data first, make the transfer, and then uncompress everything to the destination drive. The advantage of reducing the size of the data to be transferred is to save bandwidth. This is particularly useful with networks with limited speeds like Wi-Fi or 1 Gbps Ethernet if handling multi-GB files.

Unfortunately, this function respects particular rules that limit its actions and its possibilities. For example, Microsoft has implemented a threshold of 100 MB compressible in the first 500 MB of a file. As a result, small files do not benefit from this compression. Similarly, large file transfers can suffer if the first 500MB don’t offer this level of compression.

This rule can no longer be applied. SMB compression ignores the size of the data. Clearly, all files benefit from a compression request during a transfer. However, Microsoft says that not all files are “equal” when it comes to compression. Already compressed files, such as images in JPG format or files in ZIP and RAR format, do not benefit from this advance.

Windows 11 and SMB compression, details

Users, administrators, and applications can request compression. New policies and PowerShell commands can be used to control this feature.

microsoft details

group policy

\Computer Configuration\Administrative Templates\Network\Lanman Workstation

  • Disable SMB compression
  • Use SMB compression by default

\Computer Configuration\Administrative Templates\Network\Lanman Server

  • Disable SMB compression
  • Request traffic compression for all shares

All of these write to the following location and will override the ‘native’ registry setting as usual with group policy:


PowerShell for SMB client

Set-SMBClientConfiguration [-EnableCompressibilitySampling ] [-CompressibilitySamplingSize ] [-CompressibleThreshold ] [-DisableCompression ] [-RequestCompression

  • -DisableCompression $true or $false – never compress even if requested by server or application
  • -RequestCompression $true or $false – always request compression even if the server or application did not specify it
  • -EnableCompressibilitySampling $true or $false – control legacy sampling behavior
  • -CompressibilitySizeSampling 1- – size in bytes of range to sample in a file looking for compressibility
  • -Compressible threshold – 1- – size in bytes of compressible data that must be within that range

You shouldn’t need to touch the sampling settings without a good reason. Maybe hit me up in the comments first if you feel the need to touch them. 🙂 A perceptive reader might notice that a range of 9,007,199,254,740,992 is not the Uint64 in PowerShell. This is because the actual limit in the code is 9PiB, not the 184,467,440,737,095,551,615 bytes of a UInt64 value that we had to set to Posh. If you have individual files larger than 9 petabytes, I’d love to hear your story, regardless!

These values ​​are stored in the registry under:


Name Guy Flaw Boundaries PS interface (Set-SmbClientConfiguration)
Enable compressed traffic REG_DWORD 0 0 or 1 Request Compression
disable compression REG_DWORD 0 0 or 1 disable compression
EnableCompressibilitySampling REG_DWORD 0 0 or 1 EnableCompressibilitySampling
CompressibilitySamplingSize REG_QWORD 0 0 to 8 GDP CompressibilitySamplingSize
Compressible Threshold REG_QWORD 0 0 to 8 GDP Compressible Threshold

PowerShell for SMB Server

Set-SmbServerConfiguration [-DisableCompression ] [-RequestCompression ]

  • -DisableCompression $true or $false – never compress even if client requests it
  • -RequestCompression $true or $false – Always request compression even if the client didn’t specify it.

These values ​​are stored in the registry under:


Name Guy Flaw Boundaries PS interface (Set-SmbServerConfiguration)
Enable compressed traffic REG_DWORD 0 0 or 1 Request Compression
disable compression REG_DWORD 0 0 or 1 disable compression

This change will be implemented on Patch Tuesday in September 2022. If you want to take advantage of it now, you can manually trigger the download of the latest optional updates released by Microsoft. These are KB5016693 for Windows Server 2022 and KB5016691 for Windows 11.

Windows 11 optional update KB5016691 is available, what’s new?

#Windows #networks #Microsoft #speeds #file #transfers #GinjFo

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