I look for other related topics, but I did not found my answers at the moment
I haven't opened a support case, as this is more a configuration question
Some basic infos first :
- Veeam B&R 9.5u4, vSphere 6.5, 2 sites
- Veeam server on a VM (win2016)
- 1 physical server with proxy + repository roles, in each site (win2016)
- ReFS and synthetic full used on backup and backup copy
- among other few VMs, there is 2 big VMs, 1 each site, each with around 15 TB of datas
- Backup Jobs keeps 31 restore points
- Backup Copy Jobs keep 7 restore points ad GFS 12 monthly, but we got to change it, and this is the big question here
We had a big issue with past ReFS partition, with RAID6 issues and corruption, it seems all due to a bad firmware on the SmartArray RAID card when array was created.
So it was a real mess, and now we started everything fresh since a week
What is needed here is to have precisely GFS monthly backups, without any holes in it, even 1 day or some hours
It is mandatory for legal reasons
So we recreated Backup Copy Jobs with GFS 12 monthly (in the past it was 52 weekly), start interval is at 6am.
But obviously we cannot keep default setting for monthly "first sunday of month", because sometimes it will be the 3rd of the month, next month the 5th e.g, and we will have a hole in backup between the 3rd and the 5th
I hope at least a part of it is clear here...? Well, hope is the start of hapiness, but does not resolve anything

Now I see I can modify my monthly GFS to 1st day of month
It could work for us, but what are the cons to do that ?
AFAIK Backup Copy Job copies an increment from source each day and create a synthetic full the day we specify in its restore points, here saturday
And it keeps the full for archival purpose if we ask in GFS, but until now it was only once a week
So when 1st day of month wont be a saturday, what will happen ? It will create 2 synthetic full in the week ?
Also if we change this setting now I read it will keep 2 full backup with same flag, during 1 year, is it ?
It will still be synthetic fulls with ReFS optimization I suppose (fast clone and space savings)
Please help, any advice would be most welcome