[Samba] macOS performance issues

[Ian Klemm]

Hi, 


I’m currently setting up a samba Server on a Raspberry PI 4 with an external 8TB HDD.

Since this is rather low end hardware, I’m trying to figure out which performance optimizations are still relevant today, since a lot has chanced in the past years and quite a few options are now set by default.


The default values seem to work well for Windows but I’m having lots of issues with macOS. 
Even tho I’m able to hit the same maximum speed, the write speed often drops to 200-600Mbit/s and I can’t figure out why.


max          971.06 Mbit/s
average      706.49 Mbit/s  
min          304.47 Mbit/s


The HDD definitely isn’t the bottleneck. 

root at nas /mnt/hdd # dd if=/dev/zero of=testfile bs=1G count=5 oflag=direct
5+0 records in
5+0 records out
5368709120 bytes (5.4 GB, 5.0 GiB) copied, 33.1576 s, 162 MB/s

$ uname -a
Linux nas 5.4.51-v7l+ #1333 SMP Mon Aug 10 16:51:40 BST 2020 armv7l GNU/Linux

$ smbd -V
Version 4.9.5-Debian



I’d appreciate any tips since I’ve been struggling with this for the past few weeks.

Kind regards
Ian