Commvault introduced a neat little option called “Backup Failed VMs only (Virtual Server)” which can be found in the advanced settings of the schedule policy backup task.
I reconfigured the schedule policy according to the following strategy:
(i) Backup task 1: daily incremental @ 7PM CET
(ii) Backup task 2: weekly synthetic full @ 10AM CET (DASH full only; no backup)
(iii) Backup task 3: daily incremental for failed virtual machines only @ 6AM CET