VBO365 (JET-based) and Proxmox deduplication

[tdthomas]

Hi,
if I have a Windows VM with VBO365 on a Proxmox Hypervisor with a JET-based default backup repository (C:\VeeamRepository), what can I expect if I backup this VM (and the MS365 data on the backup repo inside) via Proxmox Backup Server?
Of course the run time for the VBO365 backup job would not overlap with the time of the snapshot and subsequent backup to PBS.

I am concerned that due to the nature of a JET-based backup repo, the backups made by PBS might have little to no deduplication and therefore are almost full backups in size. This would be a problem for daily backups. Has anyone experience with this kind of situation?

I would rather not use several external backup targets for VBO365, but instead integrate the backup of the VM and MS365 data into the overall backup strategy used on the PBS.

Thanks in advance,
Thomas

[Polina]

Hi Thomas,

At Veeam we have never tested such a scenario, so let's see if any of our community members can share their experience.

2 cents from my side: Even if your VB365 backups are not running, repository database can still have active reads/write at that moment. For example, retention is initiated once there're no other active tasks (such as backup or restores). To ensure the consistent state of snapshots, I'd recommend stopping VB365 services for time of the snapshot.

[tdthomas]

To ensure the consistent state of snapshots, I'd recommend stopping VB365 services for time of the snapshot.

As far as I know, this is usually achieved via the fs-freeze QEMU Guest Agent command. On Windows, it will also trigger VSS (with VSS_BT_FULL as default).
Does VBO365 rely on VSS or will it not care about VSS_BT_FULL?

Otherwise, VSS_BT_COPY instead of VSS_BT_FULL would probably be not so nice, because MS says "However, the backup history of each file will not be updated, and this sort of backup cannot be used as the basis of an incremental or differential backup."