[ixpmanager] Discrepancies between sflow hosts

[Ian Chilton]

Hi,

I’m working on replacing our old sflow host, which has been working 
for many years but has grown outdated - an old Debian release, old 
version of the IXP Manager scripts, sflowtool etc.

I’ve deployed a new host and got everything working.

This evening I was hoping to switch over. I added a 2nd sflow 
destination to all of our switches.

I have a test IXP Manager instance pointing to the new sflow host and 
our current instance pointing to the old host.

However, on the P2P graphs, the values coming from the new host are much 
lower than the old host - up to 50%. This is reflected in both the Cur 
values and the graphs themselves.

I confirmed using tcpdump that there was sflow packets arriving from 
every edge box.

I wondered if it was because I’d enabled journaling on rrdcached on 
the new host, so I disabled that.

I removed the new sflow destination from the switches and instead added 
a new sflowtool fanout destination on the old host, pointing it to port 
6343 on the new host.

I still observe the same behaviour.

Anyone had anything similar? - or have any tools or ideas to help 
analyse the data and what might be going wrong?

Thanks,

Ian