Symptom
On Nexus 93180YC switch, QoS policy can fail to apply if LLFC configuration is applied to more than 51 ports. For upto 51 ports, LLFC configuration is applied without any problem.
If the configuration for LLFC is applied to all 54 ports initially and then QoS policy is configured then the policy will fail with the following message
n9k(config-pmap-nq-c)# system qos
n9k(config-sys-qos)# service-policy type network-qos my_network_policy
(config-sys-qos)# service-policy type network-qos my_network_policy
Unable to perform the action due to incompatibility: Module 1 returned status "Ingress buffer allocation fail"
Conditions
Configure LLFC on Nexus 9000 Switch, as per the following configuration guide
Cisco Nexus 9000 Series NX-OS Quality of Service Configuration Guide, Release 7.x
Chapter: Configuring Link Level Flow Control
https://www.cisco.com/c/en/us/td/docs/switches/datacenter/nexus9000/sw/7-x/qos/configuration/guide/b_Cisco_Nexus_9000_Series_NX-OS_Quality_of_Service_Configuration_Guide_7x/b_Cisco_Nexus_9000_Series_NX-OS_Quality_of_Service_Configuration_Guide_7x_chapter_01010.html
Workaround
Configuration currently can be applied successfully for any 51 ports within the switch.
Further Problem Description
