Yeah I've been reading hard and come to that conclusion. I've worked with our consultant and we've given the disk another 1Tb of SAN storage and we'll see if it cleans up tonight. We're working on the basic that VEEAM failed to create the third full backup properly due to lack of disk space and as that failed it did not clear out the initial weeks full backup set (full & incrementals).
It does seem very difficult to achieve what we want which is a weekly full backup on a Friday night, followed by daily incremental backups Monday through to Thursday, that to repeat for a second week and then on the third week the initial backup set be deleted and a fresh one created.
The consultant setting retention to 6 does not make sense and that is what I guess is throwing me. I could see it being 2 (as in 2 full backups) or 10 (2 full sets of 1 full backup and 4 incrementals) - whereas 6 seems somewhat in the middle.
It's not helped that with our old VEEAM system the retention figure was set to 2 and that did work to maintain a weekly full backup on a Friday night, followed by daily incremental backups Monday through to Thursday.
It all seems highly illogical
I've spent all day reading VEEAM KB files and the manual and I'm still no wiser as to what we should set as a configuration to get what we need or how to validate that 6 figure to be correct.
I'm quite happy to share all our config date if anyone can solve the mystery