Windows Server Backup erased previous restore points - why, how to catch, how to prevent?

Question

Backup

There is a server configured with Windows Server Backup'om daily copying folders to the NAS, connected via iSCSI. The server was physically moved (stopped in a regular way), the backups were checked, the recovery was checked (!), left alone, after which the next backup recreated the VHD with the loss of backups for six months.
There are three questions, in general:
1) Why can Windows Server Backup overwrite VHD, where does it backup?
2) How to tell him not to overwrite if the backup interface is, to put it mildly, poor and does not even allow you to set the frequency of full backups (i.e. backup one full backup for the first time, then each time incremental backups to the same VHD, and separate task merges snapshots inside VHD)?
3) How can (at least after the fact, if it doesn’t come out in advance) find out if wbadmin start backup will overwrite the VHD?

Answer 1

1) Usually due to lack of space.
2) Yes, the interface is normal there, everything is quite flexibly configured, at least the necessary things. Since you described it by default and does.
3) Estimate the availability of space on the target volume

Answer 2

Why can Windows Server Backup overwrite VHD, where does it backup?

From your description it is not at all clear what you did with the server and how you changed the backup settings. One of the assumptions is that they changed the SID .