We have the same problem as above. We're trying to backup across the wan incrementally, which works OK. It takes about 1hr 30mins to do the backup each night. When it comes to doing a new full, or synthetic full, we're talking 44hrs+. We're not sure how long it actually takes as it's soooo long that the backup stopped (maybe due to a network glitch).
In it's current state it renders WAN backups useless
OR am I missing a trick somewhere?
I know we can use rsync to 'fix' this, but this relies on us having enough storage to do the backups locally so that we can rsync them across the WAN, which we don't have in all our cases.
I second the suggestion for an offsite 'rollup' utility or similar. Without it, or something similar, we'll have to rethink our deployment of VB&R across our small sites (of which we have hundreds!)