DSM7.2 Multichannel between DSM, Windows and macOS

[Robbie]

I've got a bit of a weird one with SMB Multichannel. I've used Multichannel on DSM pre the 7.2 update with the usual CLI changes and I have left them in place on the Rackstations that Synology omits from its ethereal list. The NAS I have on the approved list (RS1221+) has multichannel selected on the GUI but it only has a single 10 GbE link at present.

All my NASes signal that MC is on and working. As per usual macOS displays its unwillingness to embrace SMB MC, Windows just gets on but DSM to DSM seems to fail when once it worked just fine. This has regressed with DSM 7.2, at least for me.

An example from the resource monitor on my RS819:

First trace is to/from a Windows 10 server (10 GbE) showing full use of SMB MC. Second trace is the ever-truculent macOS (10 GbE) just passing traffic on a single LAN link, again. Third trace is a DSM to DSM data transfer (happens to be HB in this case) just sticking to a single interface. On DSM7.1 SMB multichannel between NASes worked fine.

Anyone else run into the DSM7.2 to DSM7.2 multichannel weirdness?

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[Rusty]

Anyone else run into the DSM7.2 to DSM7.2 multichannel weirdness?

Confirmed it doesn't work when enabling the "official" option. I tested this back with the beta version of the SMB package when it arrived months ago, and the File Station mount from one NAS to the other didn't work. The official ticket also confirmed that and said that FS does not support it atm.

Also, 819 is not on the approved support list for MC based on the limitation section inside the SMB release notes.

Limitation

1. Please note that currently the SMB3 Multichannel function only supports x86 platforms. For models in x86 platforms, please refer to all models listed in this article.

Release Notes for SMB Service | Synology Inc.

Release Notes for SMB Service | Synology Inc.

www.synology.com

On the macOS, this should work (for the Intel-based one), but again, considering the notes, Apple SOC ones won't work (and does not work for me). Still, 10G to 10G transfer with no multi-channel (mac to nas) does work, but that's expected.

 

[Robbie]

Also, 819 is not on the approved support list for MC based on the limitation section inside the SMB release notes.

Limitation

1. Please note that currently the SMB3 Multichannel function only supports x86 platforms. For models in x86 platforms, please refer to all models listed in this article.

Just a Synology choice rather than a real limit and, as said, I've been running SMB MC on this RS819 in this config for quite a while. Presumably they are applying more market segmentation in the GUI rather than actual capability. Of course, Synology didn't make Samba either!

One thing I didn't try was unofficial DSM MC to another unofficial DSM MC. I'll give that a go when I get chance. I also noticed that the official version of DSM MC does not have the normal config files you usually see for SMB MC. It still advertises multichannel in the same way though:

[email protected] ~ % sudo smbutil multichannel -a
Session: /Volumes/Video
Info: Setup Time: 2023-05-25 18:48:23, Multichannel ON: yes, Reconnect Count: 0

All my networked Macs are ASi rather than Intel so I have got used to Macs now being awkward with MC. Running them all at 10 GbE though, so hardly a bottleneck on my network.

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[Rusty]

Just a Synology choice rather than a real limit and, as said, I've been running SMB MC on this RS819 in this config for quite a while. Presumably they are applying more market segmentation in the GUI rather than actual capability. Of course, Synology didn't make Samba either!

All true