Backup always use Microsoft VSS-FULL Option and breaks other Backups

Hello!!

At first, hope i'm right here!

We use Proxmox with qemu-ga. Backups are done with vzdump (integrated in Proxmox) and Bareos for second Backup-Strategy. Proxmox creates dly Imagebackups. Bareos creates Databackup for longterm archive.

Bareos creates a Fullbackup once a day and all few hours a incremental Backup. Bareos-Fullbackup use Microsoft-VSS-Option "VSS-Full" for SQL Log-Truncating. Bareos schould be the only one who use VSS-Full. So it's guaranteed that Bareos is able to restore all data all time

Proxmox vzdump Backups use fss-freeze with Qemu-GA Agent Qemu-GA always use VSS-Full. This breaks the Bareos Backup, because after vzdump Backup SQL also truncates the SQL-Logfiles

Mybe its possible to make a switch for VSS-Full or VSS-Copy Backups. So we cat set a Regkey or something else to tell Qemu-GA to user VSS-Copy Hope also Proxmox will integrate this feature in vzdump to select the VSS Option in Backupjob.

In File qemu/qga/vss-win32/requester.cpp Line 297 VSS-Full is hardcoded.

hr = vss_ctx.pVssbc->SetBackupState(true, true, **VSS_BT_FULL**, false);

Goal

Something like that

If Regkey HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\QEMU Guest Agent VSS Provider\VssOption is set to VSS-Copy qemu-ga use VSS-Copy instead of VSS-Full

Technical details

In File qemu/qga/vss-win32/requester.cpp Line 297, VSS-Full is hardcoded.

hr = vss_ctx.pVssbc->SetBackupState(true, true, VSS_BT_FULL, false);

A Switch that the qemu-ga schould use VSS-Copy would help.

Additional information

MS VSS-Options https://docs.microsoft.com/en-us/windows/win32/api/vss/ne-vss-vss_backup_type