Inconsistent SMB/CIFS access from non-Windows clients

[HyperBlast]

I've been having an issue with clients accessing shares with a large amount of files, some flat, some with a lot of subdirectories, that all navigate normally and fast from my Windows 7/10 hosts. Any Linux or OSX host seems to have trouble browsing them where it takes an initial 10 seconds to load, anytime they are accessed. They never seem to cache.
I have no L2ARC, and am thinking I might need to give that a try. My current setup is Z2 with six 6TB disks and 32GB or ECC memory. I tried Cyerjock's guide (SMB Auxiliary Parameters) as well as a few other tweaks mentioned on here, but can't seem to improve performance. Is this a limitation with the SMB implementation on OSX and Linux? Do I just need to trim down the amount of files per share? Or share from NFS instead?

 

[nojohnny101]

L2ARC is unlikely to help you given your hardware (would be helpful if you listed full hardware specs and FN version).

What version of Mac OS X are you using?

 

[HyperBlast]

Good point, kind of dumb to leave that info out:

Build FreeNAS-11.0-U2 (e417d8aa5)
Platform Intel(R) Atom(TM) CPU C2758 @ 2.40GHz
Memory 32703MB

My OS X version 10.12.6 but I've noticed it with older versions of both FreeNAS and OS X/Linux.

Another weird note is that I did a file count of two shares and they're almost identical, so I'm wondering if there is some other issue like compressed files causing the problem. Starting to think this is a client-side issue and not a FreeNAS issue.

 

[nojohnny101]

Have you tried this modification to OS X (a known bug).
https://dpron.com/os-x-10-11-5-slow-smb/

I assume you have tested multiple client machines? Is the performance bad when browsing directories with a large number of files. What about a directory with only a few files (each files could be large in size though)?