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SNMP: filter out default sub interfaces
Closed, ResolvedPublic

Description

From https://youtu.be/bmcdqK2LATc?t=65

Adding:

[edit snmp]
+   filter-interfaces {
+       interfaces {
+           "^.*\.0$";
+       }
+   }

To all the switch stacks should speed up LibreNMS quite a bit by not exposing a type of interfaces we're not interested in.

On Juniper, all regular access ports, for example https://librenms.wikimedia.org/device/device=160/tab=port/port=18033/
Have a matching logical interface, for example https://librenms.wikimedia.org/device/device=160/tab=port/port=18036/

That logical interface doesn't expose useful information to us (everything is in the physical port stats), so filtering it out should be fine. As it's only about SNMP/monitoring, testing it out is harmless as well.

We can check the improvements using https://librenms.wikimedia.org/graphs/type=device_poller_modules_perf/device=160/from=1621240200/

Or globally with https://librenms.wikimedia.org/poller/performance

Event Timeline

Mentioned in SAL (#wikimedia-operations) [2021-05-18T09:27:11Z] <XioNoX> push test SNMP filter config on asw-a-codfw - T283060

Change 692576 had a related patch set uploaded (by Ayounsi; author: Ayounsi):

[operations/homer/public@master] SNMP: filter out default logical interfaces (.0)

https://gerrit.wikimedia.org/r/692576

Change 692576 merged by Ayounsi:

[operations/homer/public@master] SNMP: filter out default logical interfaces (.0)

https://gerrit.wikimedia.org/r/692576

Mentioned in SAL (#wikimedia-operations) [2021-05-19T07:42:24Z] <XioNoX> roll SNMP: filter out default logical interfaces (.0) to all network devices - T283060

ayounsi claimed this task.

Pushed everywhere successfully. ~2400 LibreNMS ports removed. Speed up LibreNMS pooling by ~25%.

https://librenms.wikimedia.org/graphs/type=global_poller_modules_perf/legend=yes/from=1621398000/to=1621419600/