RDMA (Mikrotik + Connect-X)

Hello folks!

With the recent updates on Mikrotik RouterOS 7.15 they’ve introduced support to PFC and ECN which are vital to enable RDMA with RoCE.

I have a setup of 3x servers with a pair of Dual 25GbE Connect-X 4 each (which supports RDMA with RoCE v2). I’d like to use two ports (one on each NIC) on each server to connect to a CRS326-24S+2Q+ (which supports the new QoS features on the switch chip) and make them to use RDMA for the storage cluster traffic on vSAN.

All ports on the switch are part of a single HW bridge using VLAN filtering. The 6 ports for the storage are on its own VLAN.

I’ve read Mikrotik docs on the QoS but I couldn’t wrap my head around its concepts.

On a Cisco Nexus switch for example, this is the configuration I would use that works perfectly fine:

!Enable Data Center Bridging (extension of LLDP)

feature lldp

!qos config for RDMA

class-map type qos match-all ROCE_CLASS

match cos 3

match dscp 26

policy-map type qos ROCE_POLICY

class ROCE_CLASS

set qos-group 3

policy-map type queuing ROCE_QUEUING_OUT

class type queuing c-out-8q-q3

bandwidth remaining percent 50

random-detect minimum-threshold 150 kbytes maximum-threshold 3000 kbytes drop-probability 7 weight 0 ecn

class type queuing c-out-8q-q2

bandwidth percent 0

class type queuing c-out-8q-q1

bandwidth percent 0

class type queuing c-out-8q-q-default

bandwidth remaining percent 50

class-map type network-qos match-any ROCE_NETWORK_CLASS

match qos-group 3

policy-map type network-qos ROCE_NETWORK_POLICY

class type network-qos ROCE_NETWORK_CLASS

pause pfc-cos 3

mtu 9216

class type network-qos c-8q-nq-default

mtu 9216

system qos

service-policy type network-qos ROCE_NETWORK_POLICY

!Run on all interfaces used for vsan/management

int eth <X/X>

lldp dcbx version ieee

priority-flow-control mode on

priority-flow-control watch-dog-interval on

service-policy type qos input ROCE_POLICY

service-policy type queuing output ROCE_QUEUING_OUT

Do we have any Mikrotik folk(s) around that could shed a light on how to configure the MT switch to achieve the same PFC/ECN settings? (ignore the DCBX settings on the Cisco example as they are not supported on MT side)

Thank you!

I really appreciate any help.

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