[Samba] Performance tuning Samba on WAN

[Alexander Harm]

Hello,

we have a Samba server setup on Debian Buster using Louis’ packages: Version 4.13.2-Debian

The server has a Xeon-E3 and a BTRFS RAID–10 over 4 SATA hard disks.

Clients connect through WireGuard VPN.

I have no problems reaching client line speed using iPerf3 in or outside the VPN tunnel. Using it makes hardly any difference.

What bothers me/us is that SMB speed is very slow. Uploadwise I can reach nearly line speed (in my case 20–40 Mbit/s) but download reaches a max of 60–70 Mbit/s (line 300 Mbit/s).

I wonder if there are any options one could set to improve SMB transfer rates over WAN.

I did set:

socket options = IPTOS_THROUGHPUT
use sendfile = yes
min receivefile size = 16384
getwd cache = true
aio is on
raw read/write too

Any tips for me?

Regards, Alexander