packet discards

Rishav Garg · ‎03-12-2015

We have a netapp storage on our Nexus and we are seeing alot of pks discarded on ingreess. I know that the Nexus does ingress queing so this seems to point to congestion on an egress port. How can I figure out what port is causing the problem or has the congestion?

I looked on Ciscos website but I can't find a good troubleshooting docutment.

qos-group 4
    q-size: 29760, HW MTU: 9216 (9216 configured)
    drop-type: drop, xon: 0, xoff: 29760
    Statistics:
        Pkts received over the port             : 5589330309
        Ucast pkts sent to the cross-bar        : 5504968963
        Mcast pkts sent to the cross-bar        : 86720
        Ucast pkts received from the cross-bar : 0
        Pkts sent to the port                   : 162325
        Pkts discarded on ingress               : 72274627
        Per-priority-pause status               : Rx (Inactive), Tx (Inactive)

Kindly help how to find which egress port is congested due to which ingress discards are increasing (I think this is a backpressure suitation)).

NXOS Version is 5.2(1)

Sebastian Helmer · ‎03-13-2015

U have jumbo frames configured? it is not bad but I just want that u know and want that.

Did you check the interface counters and see any problem..maybe do a clear counter interface before
- sh inter count erro

Is there somewhere a bottleneck, because u are right. ingress drops means there is a congestion on one of the egress..

is it a N7K?

U can check with an elam trigger where your packets are going, if u have redundacy for example..
just google for "N7K elam" u will find that e.g. which help me already to find the exact flow..use it for the module u have in place.

http://www.cisco.com/c/en/us/support/docs/switches/nexus-7000-series-switches/116647-technote-product-00.html

Rishav Garg · ‎03-17-2015

Thanks for your reply..

We don't have any N7K but we have Nexus 5548 UP model. So i checked ELAM doesn't support on N5K.

Kindly tell any other procedure to get to know which egress port is congested due to which ingress discards are increasing..?

Kindly help here...