SMB over QUIC performance issue

[Guest /u/smaxwell2]

Hi All,

 

Just as a test, today i spun up Windows Server 2025 and created a test file share.

 

I created a certificate (Lets Encrypt) and setup SMB over QUIC.

 

Mapped a network drive on a Windows 11 client.

 

I have a 1GB connection, and the Server is located in a DC with 10GB.

 

If i upload a file from the Windows 11 client to the SMB share. It maxes out the connection at around 950Mbps. But then if i try to download a file from the SMB share, it starts off very fast, but 15 seconds or later it goes to 0.1Mbps.

 

I am sure i am missing something stupid here.

 

I tried disabling SMB encryption (server side) and rebooted the Server. No difference.

 

Any ideas or things to check?

 

Update 1: Seeing event logs in SMBServer > Operational

 

Network operation has taken longer than expected.

 

Client Name: \xx.xx.xx.188 Client Address: xx.xx.xx.188:64736 User Name: DOMAIN\Username Session ID: 0xC0000000041 Share Name: \*\Test.Share$ File Name: wdav.pkg Command: 8 Duration (in milliseconds): 16485 Warning Threshold (in milliseconds): 15000

 

Guidance:

 

The underlying file system has taken too long to respond to an operation. This typically indicates a problem with the storage and not SMB.

 

However when connecting to this SMB Share not using quic with a local client, I get full speed read/write. Only get slow performance & these event logs when trying to copy via SMB over QUIC (443 UDP)

 

submitted by /u/smaxwell2

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