Another bug in vSphere 7 U3, I just read about. The backup function in the VCSA does not work in U3 any more when DB health check is enabled. Then each backup fails!
Fortunately there is a simple solution for this: run
/usr/bin/dbcc -fbss embedded in a shell-session in VCSA.
- official VMware KB article: https://kb.vmware.com/s/article/86084
- Blog post by Andrew Mauro: https://vinfrastructure.it/2021/10/file-level-backup-issue-with-vcenter-7-0-3/
This is important because you normally do not see failed backup. So when you never checks them, you would not find out the broken functionality.