[ixpmanager] Discrepancies between sflow hosts

[Nick Hilliard (INEX)]

Ian Chilton wrote on 20/02/2021 00:10:
> I just took a quick look at the debug output and it’s full of “rejected” 
> and “dropped update” lines - so that explains the incorrect data in the 
> graphs!

that sounds like your problem then.

> I assume there should really be none of those, so I guess I need to dig 
> around in the sflow-to-rrd-handler code and both start to understand the 
> understand the sflow data format and get it to output more debugging 
> about why it’s dropping/rejecting.

sflow-to-rrd-handler needs an accurate mapping of what MAC addresses are 
assigned to what port (and consequently which ixp participant).

There are two ways that it can do this: either using the configured mac 
address database, or else the learned mac address database.  These 
tables are visible in the "MAC Addresses" submenu on the LHS of the 
admin console.

By default, sflow-to-rrd-handler uses the learned MAC address database 
for this. You can get it to use the static mac address list by putting 
this into ixpmanager.conf:

<ixp>
         macdbtype = configured
</ixp>

Nick