decrease perfomance

Good day. 3 month ago average IO Delay increased dramatically, about 10 or 15 times. Nothing radically changed in VMs. Hypervisor hardware also the same. I have 17 VM running: (10 with Windows 7,10, Server 2012) and (7 with Linux Ubuntu 18.04). There are 3 disks also: all VMs on nvme0n1 (m.2...