[August 2025] MacOS SMB Performance Optimizations for TrueNAS 24.10/25.04

TrueNAS General
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(N.B.: This post is not related to Server-Side Copy.)

Hello!

To put it gently, Mac OS’ default SMB client behavior out of the box, especially when working with many small files (or just many files in general) is, well, bad. This is entirely MacOS falling down on proper SMB optimization, not a TrueNAS issue.

I know that TrueNAS’ smb4.conf already contains some MacOS-related optimizations, so I’m looking more at my client Mac now. TrueNAS’ SMB configuration also accounts for the underlying filesystem being ZFS, which generic Samba Mac optimization tutorials don’t.

A lot of those generic tutorials are contradictory and don’t explain the settings they advise, and appear to focus entirely on the server-side.

Question: Here in August 2025, is there a cohesive set of guidelines/suggestions for optimizing Mac OS’ SMB performance with TrueNAS?

I say “with TrueNAS” because a lot of guides assume a vanilla Linux Samba server is on the other end of things, and a default TrueNAS install does not start out with the same configuration as vanilla Samba.

I’m already aware of the trick for disabling the creation of .DS_Store files on SMB shares by Mac clients, and I’m using MTU 9000 because the on-board Aquantia NIC on my Mac seems to be unable to perform well at 10 Gbps without it.

Thanks!

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Not that i’m aware. Typically the solution of any issue is specific to one use case.

Most of the problems are MacOS related and some cannot be fixed AFAIK.

For example, we found that MacOS is 99% slower than Windows 11 at Directory listing. This in turn means that the max recommended files in a directory should be less than 10,000 and not 1 Million.

Of course, M4 Macs are quite a bit faster than previous, so there might even be a need to review based on Mac version.

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Thanks for your thoughtful reply, @Captain_Morgan . :slight_smile: I know that all of this is use-case specific, but as you allude to, Mac OS’ default SMB client configuration (or rather, the Finder’s) is just awful.

I’ve got some links to go through to research how to optimize those settings, and when I posted this, I was curious if someone had already put together a “make MacOS suck less at SMB” guide. Alas. :wink:

As someone who has used and loved Macs since the 1980s, things like this are just sad. There’s a lot of under the hood stuff (particularly related to network file sharing, but elsewhere, too) that Apple just doesn’t seem to care about fixing anymore.

For anyone who finds this thread later, here’s Apple Support’s instructions for disabling the storage of .DS_Store files on SMB shares, which should speed up directory listing dramatically. (I haven’t tested this yet…I’m chasing other network malfunctions this weekend. :stuck_out_tongue: )

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