1. Can I just cut & paste the VRBs onto an external drive & leave the VBK as is?
Yes, you can do that.
You need to take your .VBK + .VBRs to some other repo with enough space on it and just map your backup job to that repo. Please refer to this
thread and this
There is also another option:
First, you reduce your retention period for your current backup job thereby cutting the amount and overall size of backups being stored on your current repo. Then you setup a backup copy job
which copies your backups to some other repo as many times a day/week/ as you need and gives you an option of setting a separate retention policy for that backup copy job, so you have exactly needed amount of restore points in your archive.
2. If we ever needed to restore from one of the 'archived' months, can I just copy back the relevant VBKs i.e. the specific month and all the months in between?
Yes, you can.
You have to import
your backup file then you can treat it like a regular one.
3. Will this effect the next monthly job?
If you just delete your .VBKs from your current repo without remapping your job to a new one, then you will have to use a forcecreatemissingvbk
workaround. So, the answer is "No, if you use any of two other methods described" =)
By the way - you are dealing with days/weeks/months RPO, so I assume that GFS concept
may serve you well.
Animated GFS article
Please let me know if that works for you.