I have been testing the backup copy for future offsite backup in the past week. Right now, I am doing the backup copy to a server on our main site. The backups on the "backup copy server" have exceeded the number of restore points to keep, so every time the backup copy occurs, Veeam will perform a full backup file merge.
Let's call "backup copy server" as Server A, "Onsite Veeam Server" as Sever B.
I checked the data transmission of Server A when it was doing a backup copy (as the picture below).

I found that Server A sent large mount of data to Server B (first red peak) before the backup copy transmission (the first green peak). And the second red peak occurred when full backup file merged on Server A because of the exceeded number of restore point.
Why does server A need to send data back to Server B?
Is there any way to minimize the data send from Server A?
Do we need to deploy a Veeam backup server on offsite just for accelerate backup copy, because the size of some backup copy files are several GB?
Thank you
Ryan