Minarca Client VSS support

[Eduardo de Oliveira]

Hello,

Does Minarca Client supports VSS? It's required to backup locked files into a consistent state on Windows, e.g. PST files from Outlook while it's running.

Some useful links:

• BackupAssist (Minarca alternative) supports rsync and VSS: https://www.backupassist.com/education/articles/run-rsync-on-windows.html
• Custom scripts to create a VSS snapshot before running rsync: https://blog.jay2k1.com/2011/08/13/how-to-create-rsync-like-hard-link-backups-with-vss-on-windows/
• Simpler example from the scripts above based on restic: https://github.com/restic/restic/issues/340
• Code sample for VSS implementation (Go): https://github.com/restic/restic/pull/2274
• Python project that demonstrates VSS support through WMI: https://github.com/RatixXt/PyVSS/tree/master

[Eduardo de Oliveira]

Notice that VSS snapshot creation requires Admin Rights. Duplicate and Cobian Backup circumvents this by implementing a service which runs with highest privileges and create the VSS snapshot before running the backup task.

[Eduardo de Oliveira]

Another alternative would be running the task with SYSTEM privileges, which also would allow the task to backup folders which the current user wouldn't have access. We could also implement it simply checking "Run with highest privileges" and requesting username/password to be able to create VSS through Minarca as it does to run Minarca when user is logged off, but we would also need to check if user has Admin rights as "Run with highest privileges" option do not work if user isnt' an admin.