Thank you for your answer.
I understand the load problems on a live session. Especially on large scale fabrics, where UFM server is already quite on a load.
But if i'm right with the new scheme of ufm 4.0 and the history feature, polling of the whole fabric is continuous. On my example, i have a schedule every 30 second, I'm not anymore running live session, and history database is on a second server (not on the UFM one).
The graphical display of history is important for me to have fast overview of congestion counters.
I'll be happy to give you feedback if you have someone looking into it.
Jerome