Full + incremental sets not being groomed by DLM
Good Day,
I'm encountering an issue with Full + Incremental backup sets not being groomed properly. I understand the logic behind DLM and I've been using BE for over 10 years. Typically focus on full backups only, however due to infrastructure size and storage constraints during a growth spurt for the company, we were forced to implement a weekly Full + Daily Incremental backup strategy for our Exchange server: Full runs every Sunday and Incrementals run Monday - Friday. Every individual backup job is B2D2T (Backup to Disk and Duplicated to Tape), so I have both the full and the week of following incrementals duplicated. Using this strategy, I have enough B2D storage for about 2 weeks of history on-disk (not to mention the copies on tape that I rotate out) - 2 Full and 10 or so Incrementals.
With this strategy in mind, one would think that DLM would groom out the first Full and first week's worth of Incrementals after the second Full backup is performed successfully, verified and duplicated to tape. This, however is not occurring. The B2D targets are filled up with 2 weekly Full backups + 2 weeks (10+ days) of Incermentals and when week 3 begins and the 3rd Full backup begins to run, it hangs with storage errors stating that there is not enough disk space available. I have tried manually expiring the oldest set of backups (The first Full and first weeks of Incrementals), however BE still does not groom the files. So, I am forced to perform a hard delete on the older backup sets and snapshot folders, (which allows the week 3 backup to continue/complete), then perform an Inventory/Catalog on the B2D volume which removes the older (already deleted) backup sets from the Storage > Backup Sets view in the BE GUI.
I have the data retention for those backup sets configured to a low value (only a few hours or days) which allows the backup sets to expire long before I need them groomed and I rely on the fact that BE will not delete the last avaialble backup set (and dependants) required to perform a restore. This works correctly.
I have the global storage settings to: Overwrite Recyclable media before scratch and Allow Backup Exec to delete all expired backup sets is [OFF].
So as far as I can tell, the behavior by design should be that BE should delete the First weekly Full backup and dependant Incremental backup sets at least once the second weekly Full is completed/verified (which would be a successful SDR backup).
At the very least, after the first and second Weekly Full backups fill up the volume, when the 3rd weekly Full backup is run and encounteres a low storage condition, DLM should groom out the first full backup and subsequent first set of dependants - which it does not. Ideally, it should not even get to the point of needing the low disk space condition since DLM should delete the first Full + Incrementals after the second Full is complete.
Can someone point me in the direction of what may be missing here or if there is some other flaw/bug that is causing this behavior?