Retention Policy Question Version for images are restore points. Keeping 2 versions when you are running a full every 30 days may not do what you want. You would run:
1 - full
2 - incremental - now you have 2 versions
3 - incremental - need to keep it because you only want two and those two are this one and the previous incremental since incremental backups are chained - but the full is needed for those restores so it needs to stay too
4...29 - same thing
the next set runs and
1- full - now this full and the previous incremental are your 2 versions, but since that previous incremental needs all the backups in that set, everything stays
2 - incremental - now you have 2 versions - this incremental and the full before it and now the previous backup set (full + 29 incremental backups can be removed)
3 - same as previous backup set example
To do what you want, keep 30 versions. You'll end up with 60 backups before the first 30 can be removed and that cycle will repeat.