libvirt users - Apr 2017 - Windows Guest Server 2016, bad performance of whole virtualisation system

hello ,
i did a kvm guest with virt-manager and installed windows server 2016.
performance settings for the disk: hypervisor default  for cache & io 
mode

i added a 2nd disk to the guest , also with hypervisor default settings 
on cache & io mode
Under disk settings in windows server 2016 i set "format whole disk 
NTFS"
i did not choose the "quick format" option.

when windows is formatting this 1TB drive the performance on the 
virtualisation host goes down
loging via ssh take ages, top take 2 mins to start up.

the physical disks are connected to a raid controller LSI and FS on 
virtualisation server where the qcow2 files are is XFS.

DO i have to set another options for "performance options" as 
"hypervisor default" to keep the system performant on formatting the 
disk?

thanks for any hints.

marko

-- 
zbfmail - Mittendrin statt nur Datei!