Very slow write speeds with 10gb

I don't have 10Gbe at home, but we do have some stuff running that speed or faster at the office in a SAN.

While this means I can't help you directly, I can say that generally we have not had to tweak any settings on our current setup, but on our previous one we did have to do some driver tuning to get the speeds up where we expected them (this was using iscsi protocols, so not the same as samba). As a rule in terms of being able to make use of the network speeds, linux was the fastest, followed by MacOS (about -20%), then Windows (about -40%)

The best place to look for documentation is usually with the NIC manufacturer to see if they have some driver tuning guides.

There are also some samba settings that can be implemented in the extra option section of your shares that can increase performance by adjusting samba buffer sizes, raw read, etc. These options can be found in the samba configurations documentation, and you may also find some information via general googling about 10Gbe and samba.

I'll also say that you should not expect 10 times the performance of 1Gbe because samba is a very chatty protocol and it is still single threaded if I am not mistaken, so realistically the most you might see is about 1.5 to 2 times the performance on a per file copy.

If you look at the below link (about half way down the page), there is a samba multi-channel option if your samba versions are high enough, that can improve performance by bonding several transport sessions together (sort of like mult-threading), but both server and client need to be at a high enough version and it needs to be enabled in the installation on the system. I don't know if this is implemented in the windows samba build and it is "experimental" in linux, so it may or may not be available in the debian build, as debian tends to lean toward stable and not experimental. I only run 1Gbe, so even if I enable this option I can't really test it since I can saturate my 1Gbe with a single samba transport session. The current samba in OMV7/Debian 12 is 4.17.12, so this option may be in there by now, I would have to go pour through release notes to confirm, and it is way too late here to do that.

Samba 4.4.0 - Release Notes