W11 - Change to client Registry doubled the speed of VV Copy

[Alice]

Right so I made a change to W11 Pro 23H2 Registry that I read about here :

learn.microsoft.com/en-us/windows-server/administration/performance-tuning/role/file-server

under the title : General tuning parameters for clients

and to a degree here :

learn.microsoft.com/en-us/previous-versions/windows/it-pro/windows-7/ff686200(v=ws.10)

I added DirectoryCacheLifetime DWORD (32-bit Value) to :

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\LanmanWorkstation\Parameters

with a value of '0', then rebooted.

Copies are as below from W11 PC to Windows Server 2022.

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speed of VV6 copy before reg change :

-- Done: 45,941 (22.99GB) Err: 0 (0) Skipped: 0 (0) Tot: 45,941 (22.99GB) --
-- Average Transfer Rate: 80.23MB/Sec -- Elapsed Time: 4 min 53 sec

speed of VV6 copy after reg change :

-- Done: 45,985 (23.01GB) Err: 0 (0) Skipped: 0 (0) Tot: 45,985 (23.01GB) --
-- Average Transfer Rate: 170.79MB/Sec -- Elapsed Time: 2 min 17 sec

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Amazing and totally unexpected.

Assume it's 'safe' to make that change....I guess it could increase other network traffic and reduce overall server performance as there is no 'cache', but as this is my 'home network' and comparatively high-spec I doubt that will matter too much.

[TGRMN Software]

Hi Alice, this is strange and I want to test it as well! Setting the DirectoryCacheLifetime to 0 effectively should disable caching of the directory content over SMB, this should actually slow down applications?
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TGRMN Software Support
http://www.tgrmn.com
http://www.compareandmerge.com

[Alice]

So the speed gain maybe only occurs if there has been a mass delete of the Destination immediately before a 're-copy' to it.

Relates to this call :

https://www.tgrmn.com/web/forum/viewtopict6396.htm

I tested it again this morning, with the registry set then unset. The copy job is double the speed if the DirectoryCacheLifetime is set to '0'.

However for a VV6 copy to a new folder on the Destination, ie not one that has just had its contents deleted, it is as you predicted slower.

Q) Would VV be able to programmatically flush the cache ? Could you offer it as a program option perhaps ?


tks


A.