During the hot backup of Hyper-V host OS, the guest OS is stopped for a few minutes.
This behavior is by design of hot backups using VSS snapshot.
In the event of the following conditions, the guest OS during a hot backup of the host OS does not stop.
1) Hyper-V integration services are installed.
2) Dynamic disk does not exist in the guest OS.
3) The entire volume of the guest OS is formatted with NTFS.
4) All of NTFS volumes of guest OS is greater than or equal to the capacity 1GB, and there is free space of at least 300MB. (VSS Limitations)
5) Guest side have disabled the previous shadow copy version function, or is set to the same volume.
6) Guest OS is running.
7) OS that VSS can be used. (Windows XP and later Windows system)
In addition, a guest OS on a volume that is not included in the backup does not stop.
Disk0 system reserved area | C :(system)
Disk1 D: volume (there is a guest OS file)
If backed up the Disk 0 in the above configuration.