I recently found out that my vCenter Server Appliance (VCSA) scheduled backups had been failing for some time but I was not aware. While there is a default vCenter Server alarm for failed VCSA backups, however it is only visible when you have selected the vCenter Server inventory object in left hand navigation, which is not a typical item that I select as shown in the screenshot below.
Furthermore, I was actually logged into the VCSA's VMware Appliance Management Interface (VAMI) not too long ago while updating to a newer patch release and I had checked to see if backups were successful, which I thought they were when looking at the "Status" column.
It was not until I took a closer look, did I realize that the schedule backup activity log is ordered from oldest to newest, meaning what I saw was a backup that has happend a long time ago and not necessary the latest backup attempt. I found this to be a really strange UX since as you would need to page to very end to check whether the latest backups were succssful or not.
Note: I have already filed an internal bug to ask for the VCSA schedule backup activity to be ordered from newest to oldest, so users can quickly see if the latest backups are successful or not.