Almost certainly a configuration we have never officially tested - which kind of makes it into an "Alternative Configuration" where it might work but it would be up to you to test and understand any limitations.
A thought springs to mind that whilst it might let you get at the files - it probably can't protect Access Control lists (ACLs) against the security of the file system within NTFS and you may even struggle with things like Incremental Backup Jobs as well.
Thanks to you both. The issue is that dual-boot is a customer requirement, and the Windows instance is likely to have a harder time garbbing the Linux files than vice versa.
There may be a way to schedule a boot into each OS to back them up with the proper agent, but I don't know what that is at the moment.
If scheduling and compute power (and space) sufficed, I wonder if dd if=/dev/rsd01c | tar -czf /var/windows/disk.tar.gz (or something like that) before backing up Linux might help.
Kind of strange to have dual boot these days as single booting and running a workstation based virtualization product has become the more usual practice because then an individual user can access both environments quickly.
If you're saying that a license for each OS is necessary if each is booted to be backed up, certainly. Are you saying two licenses are needed if WIndows is presented to the Linux instance as a mounted volume or an tarred file?