VM snapshot status reports "QuiesceFailed" for Windows VMs under high I/O load in OpenShift Virtualization

Issue

• When taking a snapshot of a Windows Virtual Machine (VM), the VirtualMachineSnapshot resource reports a QuiesceFailed indication in its status, even if the filesystem freeze eventually succeeds inside the guest.

# oc get vmsnapshot <snapshot-name> -o yaml | yq '.status.indications'
- GuestAgent
- Online
- QuiesceFailed

• The virt-controller logs report a timeout (approx. 5 seconds) waiting for the freeze command:

{"component":"virt-controller","level":"error","msg":"Failed freezing vm win2k19-fuchsia-pig-14: Internal error occurred: unexpected return code 400 (400 Bad Request), message: server error. command Freeze failed: \"LibvirtError(Code=86, Domain=10, Message='Guest agent is not responding: Guest agent not available for now')\"","pos":"source.go:353","timestamp":"2025-12-04T19:36:25.635052Z"}