[German]Brief note for administrators in companies that use Windows 11 as a client and Windows Server 2022. Microsoft has made improvements to SMB compression behavior and changes to settings. This is according to a blog post from last in the tech community.
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Preview update for Windows 11/Server 2022.
Last week, Microsoft released some preview updates for Windows 11 and Windows Server 2022. So there's update KB5016691 for Windows 11 (see Windows 11: Preview update KB5016691 (August 25, 2022)) – and there's update KB5015879 for Windows Server 202 (see Windows Server 2022 Preview Update KB5016693 (Aug. 16, 2022)). The descriptions of both updates also mention a new feature in Server Message Block (SMB) Compression, without revealing any further details.
The Server Message Block (SMB) protocol is a client-server communication protocol used for sharing files, printers, serial ports and other resources on a network. It can also be used transaction protocols for communication between processes.
What's new in SMB Compression
In the SMB compression behavior & settings changes blog post Ned Pyle from Microsoft Microsoft's Techcommunity goes into a bit more detail about what's new.
The old approach
Previously, SMB compression used a standard algorithm in which it attempted to compress the first 524,288,000 bytes (500 MiB) of a file during transfer and track that at least 104,857,600 bytes (100 MiB) were compressed within that 500-MiB range. If less than 100 MiB could be compressed, SMB compression was set to compress the rest of the file.
If at least 100 MiB was compressed, SMB compression attempted to compress the rest of the file. This means that very large files with compressible data – for example, a multi-gigabyte virtual machine disk – are likely to be compressed, but a relatively small file – even a very compressible one – was not compressed.
New approach to compression
The release of Windows Server 2022 update KB5016693 (OS build 20348.946) and Windows 11 update KB5016691 changed this feature of SMB compression.
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Now, when compression is requested via SMB, Windows attempts to compress the file, regardless of its size or apparent suitability for compression. It doesn't matter how the compression was requested – Robocopy, share setting, registry values – Windows will attempt to compress the file.
For already compressed formats such as JPG, ZIP, DOCX, etc., SMB compression does not bring any benefits regardless of their size. VHDX, ISO, DMP and other large files with a lot of white space are compressed quite well. However, this means that when smaller, less compressible files are transferred, an unnecessary amount of CPU time is spent on compression. Administrators should keep this in mind and not be surprised if copying many such files over a network then takes longer. Microsoft has released this video demonstrating the changes.
Other changes
In addition, there are now a number of Group Policy, PowerShell and registry options that administrators can use to control legacy behavior and avoid manually editing the registry to configure client compression. The details can be read in the blog post SMB compression behavior & settings changes. (via)
