Having recently done our first full backup of our Enterprise 10.6.1 environment, yesterday I was surprised to find that the server had maxed out its C drive space. The culprit was Enterprise backup files in this portal folder:
C:\arcgisportal\backup\walarchive
The files in here just keep being created and created until they take up huge amounts of space - clearing it freed up 16gb. I gather from talking with local technical support that these are related to incremental backups, which we are not yet doing, but it seems an oversight to me to have Enterprise/portal filling up your critical server's C drive. I would suggest that there needs to be a solution found to this. In my view it should not rely on customers finding this problem when the C drive fills up, then having to manually clear several gb of files.
Of course backups are great, and it's great that we're able to do a full or incremental backup and restore our server/portal in case of disaster. I just think this needs looking at.