How can a no-drop policy be configured for iSCSI traffic in Nexus 5548UP ? Are there any adverse effects ?

[Ashwin Shaji]

How can a no-drop policy be configured for iSCSI traffic in Nexus 5548UP ? Are there any adverse effects ?

[mahising · Accepted solution]

hi,

Adverse effect depends on the your network config but i can tell you how to config no drop policy for iscsi traffic...

we have three steps configuration in Nexus below is image ...

1. QOS class-- for initial classfication of traffic

2. Queueing (INPUT/OUTPUT) -- this is where you reserve or police traffic

3.Netwrok QOS -- where you prioritze or set MTU for classified traffic at backplane which fabric in nexus

 

(config)# class-map type qos myTraffic   // Match ISCSI traffic 
(config-cmap-qos)# match protocol iscsi

#policy-map type qos myQoS-policy  // Set qos group 2 for ISCSI traffic  so that it can be recognized 
  class myTraffic
    set qos-group 2
  

(config-cmap-que)# class-map type network-qos myTraffic  
(config-cmap-nq)# match qos-group 2

(config-cmap-nq)# policy-map type network-qos myNetwork-QoS-policy
(config-pmap-nq)# class type network-qos myTraffic
(config-pmap-nq-c)# pause no-drop
(config-pmap-nq-c)# mtu 2158
(config-pmap-nq-c)# sh policy-map type network-qos myNetwork-QoS-policy

(config-pmap-c-qos)# class-map type queuing myTraffic
(config-cmap-que)# match qos-group 2

(config-pmap-nq-c)# policy-map type queuing myQueuing-policy
(config-pmap-que)# class type queuing myTraffic
(config-pmap-c-que)# bandwidth percent 50
(config-pmap-c-que)# class type queuing class-default
(config-pmap-c-que)# bandwidth percent 25
(config-pmap-c-que)# sh policy-map type queuing myQueuing-policy

(config-sys-qos)# service-policy type qos input myQoS-policy
(config-sys-qos)# service-policy type network-qos myNetwork-QoS-policy
(config-sys-qos)# service-policy type queuing input myQueuing-policy
(config-sys-qos)# service-policy type queuing output myQueuing-policy

let me know your any concerns 

[Ashwin Shaji]

Hi Mahi,

Thanks alot for your reply. This helps alot. 

I have a few queries from this.

1) Since a bandwidth policing is applied globally for iscsi how will it affect my other ports that run native fc and fcoe. ?

2) Is there a way I can test and make sure my iscsi packets are indeed not being dropped?

3) Is the MTU size of 2158 flexible ?