I have a Truenas Scale server set up on my LAN serving an SMB share. My desktop is running Debian trixie all up to date. There is a 2.5G ethernet link between them (10g on the NAS, limited by 2.5G on the desktop).

Debian is set up to automount the share via CIFS on boot time into a folder in /media.

When writing large groups of media files to the NAS, performance from Linux is very slow. It sends data only intermittently. When monitoring network traffic, you can see where the Debian file transfer window will show progress while network traffic is paused; then the file transfer window will stop moving when network traffic increases. It does this for the entire contents of a single file (e.g, 1.5gb at a time for the media I was moving). It almost acts like it is filling an internal cache with the file then writing that cache out before streaming the next file… Now, this is a Debian only problem. When I reboot into my Windows 11 install, this problem disappears- transfers run at full line speed as expected, no delays. So I am ruling out an issue with the Truenas box.

Is there a configuration setup in Linux that I may have set wrong for interfacing with an SMB share? Something I need to do to change? I’m not that good at the Linux, I was able to get the SMB share working from a guide but that’s about the limits of my knowledge lol.

edit: if it helps, I am just using CIFS to mount the drive using the following line in /etc/fstab:

//truenas.local/bruh2 /media/bruh2 cifs credentials=/home/<username>/.smbcredentials,rw,uid=1000,gid=1000 0 0

That is the only configuration I set.