NetFlow monitored interfaces

Question

I've setup netflow in my solarwinds environment and I've just started to add a few L3 vlan's for testing. Added our firewall interfaces as well. Guess my question, is there a limit to the amount of monitored interfaces to send flow traffic? Will switch/router cpu and memory suffer if i add to many interfaces?

How many interfaces do you guys generally monitor with NetFlow? Just the "important" stuff or all of it?

I have about 300 L3 vlan's to monitor including a few interfaces on routers here and there.

Thanks.

mesverrum · Answer

I've seen it both ways. Some clients will just monitor every interface for all traffic, but I find that just makes your NTA screen bloated with irrelevant info, you usually are only interested in key choke points like wan interfaces and similar.  If you have gig(10,40) links between infrastructure then you are rarely going to be interested in what is moving across the infrastructure trunks, you typically just want to keep an eye out for the bottlenecks.