[c-nsp] QOS Tx Drops on N3k

[Saku Ytti]

Hey Sergey,


Your intuition seems right. My initial guess as well would be that
these are consequence of microbursts. So any effort to understand
buffer utilisation is needed to exclude or prove that.


Do you have ingress ports operating at 100GE or do you have multiple
10GE ingress ports competing for that 10GE egress port?


On 18 March 2018 at 00:52, Sergey S. <gforgx at fotontel.ru> wrote:
> Hi,
>
> I'm running NXOS 7.0(3)I5(2) on N3K-C3064PQ-10GE.
>
> Output discards counter is gradually incrementing on one 10G port despite it
> not being oversubscribed in those moments of time.
>
> If I look at "sh hardware internal interface asic counters module 1" these
> drops are displayed as QOS Tx Drops.
>
> I've tried setting up "hardware profile buffer info port-threshold" even to
> the lowest values (e. g., 1%) to figure out if there is a problem with QoS
> queues, however there isn't any information in "sh hardware internal buffer
> info pkt-stats port-log" (most likely I don't understand the concept of
> buffer monitoring and/or it's totally unrelated to my issue).
>
> There isn't any special QoS configuration on the switch. It is just as
> follows:
>
> policy-map type network-qos jumbo
>   class type network-qos class-default
>     mtu 9216
> system qos
>   service-policy type network-qos jumbo
>
> Not sure whether this gives some clue, anyway, the port in the subject is
> connected to a large broadcast domain (Internet Exchange Point).
>
> Thank you for any hint!
>
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-- 
  ++ytti