Full backup vs synthetic full backup following a CBT reset

[emjaydee]

Going to be upgrading a customer to v9u1 from v8. They currently run 3 backup jobs, all are incremental with synthetic full on weekends, one on a Friday night, the other two on Saturday. Retention period is 7 days. Problem is they are almost out of disk space and will not have enough to run a full backup for all 3 jobs following the CBT reset.
If I run the upgrade and perform a CBT reset, job 1 (Friday, full synthetic) should run a full backup. rather than the scheduled incremental and full synthetic, correct?
If I disable Jobs 2 & 3 on Friday and re-enable them to run at their scheduled time on Saturday, they too should run full backups and again there should not be a need to run an incremental and synthetic full as there will already be a .vbk file
As the retention policy is only 7 days, the .vbk and associated .vib's that are 8-14 days old should be deleted.
If this is the case then I should be able to run these jobs and not run out of disk space correct? Or am I missing something here?

[Vitaliy S.]

If I run the upgrade and perform a CBT reset, job 1 (Friday, full synthetic) should run a full backup. rather than the scheduled incremental and full synthetic, correct?

It will do a full block scan and then run incremental pass with synthetic full backup. If you want to trigger active full, then you should do that manually or explicitly select this option.

If I disable Jobs 2 & 3 on Friday and re-enable them to run at their scheduled time on Saturday, they too should run full backups and again there should not be a need to run an incremental and synthetic full as there will already be a .vbk file

These jobs will still an incremental run (after full VM scan for new blocks) and then synthesize a full backup file.

As the retention policy is only 7 days, the .vbk and associated .vib's that are 8-14 days old should be deleted.

If you only have 1 VBK file right now, then old files will only be deleted after you reach 15 restore points for the backup chain. See this topic for more info > Job Set for 14 Mount Points - 46 exist

Let me know if you have any further questions!