Meraki C9300-M QoS Settings/Configuration

[Pwellion]

Hello All

I'm in the process of replacing a customer's existing network (Cisco Catalyst 2960x switches), which has QoS enabled.
We are migrating to Catalyst 9300M switches. I'll discuss with the customer about their QoS requirements (if indeed required at all) as I suspect the configuration was in place when WAN links were much lower in terms of bandwidth.

I've read some great articles on this forum relating to QoS on the MS platform (see below links). 

https://community.meraki.com/t5/Security-SD-WAN/Meraki-MS-QoS-behavior-question/m-p/203036
https://community.meraki.com/t5/Switching/Recommended-QOS-settings/m-p/206113

From what I gather the Meraki MS provides a much more simplified QoS offering. I just want to ensure I am correct , in my assumption as the Meraki Documentation is rather limited.

1. To enable QoS I have to specifically configure vlan(s) via the below setting.

1. Switch > Configure > Switch settings. Find the section Quality of service. 
2. Click Add a QoS rule for this network

This allows me to trust the DSCP values on the specific traffic, and/or set the DSCP value if required.
By performing the above step I am automatically saying "I want to apply QoS to this traffic"

I get the DSCP to CoS mapping and also the associated CoS to Weight x 6, configurable queues.
What I can't seem to find is anything to say under what conditions QoS is applied to a link/interface. In "traditional" Cisco platforms QoS only kicked in (excluding policing, shaping) when the interface was congested, assume Meraki operates in a similar manner? Is below the only Meraki documentation on QoS for the MS switches.

Meraki Documentation

https://documentation.meraki.com/MS/Other_Topics/QoS_(Quality_of_Service)
https://documentation.meraki.com/MS/Other_Topics/MS_Switch_Quality_of_Service_Defined

Thanks

[GIdenJoe · Accepted solution]

Hey, sorry I didn't see this question before:

Meraki switches only apply the queuing and scheduling part of QoS.  So no token bucket policing here 😉

Also which is a shame, there is no strict PQ.

All Meraki switches basically have 8 shared round robin bandwidth queues where each following queue has double the bandwith guarantee than the one before it.  But if said queue is not fully utilized it will yield the remaining bandwidth to the next lower queue.
Queue 6 and 7 are reserved for internetwork and network protocols so they have the biggest allocations and queue 0 - 5 are configurable (they call it CoS queues).  So you can map DSCP EF + AF41 to queue 5 if you want the max bw for those.  You will find however that most examples only use up to queue 3 since they don't really use that 12 tier model Cisco uses to translate into switches.

So all traffic that does not get scheduled remains in the queue in memory buffer or tail dropped if the memory buffer is full.  There are no advanced tuning methods like RED/WRED or policing to avoid said congestions.