Deleting the first incremental forever full VM image?

[Newcomer]

Hi!

I'm curious what would happen if we are running an incremental forever strategy and i manually deleted the first incremental forever full image from a VM? For example; We have the first ever full backup of the VM, then 29 incremental vm backups. If i delete one of the middle incremental ones i suspect that the "chain" wouldn't be affected and that i would still be able to restore the VM to any of the 28 other points?

But what if i deleted the first ever full backup image of the vm with "delete backup -objtype=vm xxx -pick" and selected the full one? Would i still be able to restore the VM to the other points? Most likely not, but i'm curious if anyone has tried or tested this.

 

[marclant]

It doesn't really work that way. It's not a full followed by incrementals. They are all incrementals, it's just that the first backs up everything, not because it's a full, but because it compares what was backed up before to what is there now, and everything is new, so everything is a candidate for backup. Every backup will backup changed or new blocks, that's true for the first or 20th backup.

Everytime you do a new backup, it creates a restore point and it takes all the new blocks backed up and groups them with the blocks previously backed up that have not changed during this backup. So there is no full image to delete. I'm not sure of the ramifications of deleting old backups, but I'm pretty sure that if you delete the oldest backups, it would only delete the blocks that are not associated with newer backups.

That's essentially what is happening with expiration, if you retain 14 days and your first backup was a month ago, the data from 15 days and more that is not part of newer backups is expired, but those that are still valid aren't.