hey guys, just a heads up.
We had been battling to trace heavy CPU utilisation on our Re-FS layer (only during active full) since upgrading to 9.5 and all our infrastructure to Windows 2016 server.
Finally after much thrashing around trying to understand why the System task (NT Kernel & System) was flat lining and killing our Re-FS layer we finally realised on our previous architecture eon Server 2012R2 we had no AV installed whereas Server 2016 has AV installed by default, so a quick google took us to;https://www.veeam.com/kb1999
Once we put in the exceptions, our system was stable through an active full backup again.
hopefully you guys won't overlook this like we did!