Can we load balance flows between Harvesters?

Products

• Network Flow Analysis

Issue/Introduction

Can we load balance flows between Harvesters?

Such as using an Load Balancer and VIP (Virtual IPs)

Environment

Release : 10.0+

Component : NQRPTA - REPORTERANALYZER - NFA Network Flow Analysis 

Resolution

Load balancing between harvesters is not supported.


In NFA 10.0.x and later, every time a router switches between harvesters it is going to create a new instance of that device in NFA Enabled Interfaces screen.

It will mark the old one as OLD or Retired in the db and then you would have to merge the interfaces to keep historical data.

This process cannot be automated, so if you have devices switching harvesters frequently you would have to do lots of merging to keep the historical data.

Many customers use a third party tools to handle the distribution of flows to harvesters, however routers should generally stick to the same Harvester unless you are planning a one time move of the router.

Also note that after a router moves to a new harvester and if you merge the data and delete the old device, you will also need to perform a full resync of the NFA Data Source in NetOps Portal to ensure the device is fully removed from Performance Management.

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If you are looking to add Load Balancing into your deployment, The important thing to remember is that Harvesters can not support load balancing, and all Netflow traffic from one site needs to always be sent to the same Harvester, this is a 1:1 relationship.

So you can use Load Balancers to create a VIP so that all Routers in the network point to a single IP, but it still requires being mapped to the correct Harvester.  

This has been accomplished in some deployments using a port number.  For Example, the router sends netflow to the VIP:9995, this is mapped to always send to Harvester A.  Another router might send to VIP:9997, and this will always be outed to Harvester C.

The Netflow traffic can not be load balanced between Harvester as indicated above, as that will cause problems.