Frequency based backups + tape retention

[Gurnsy]

Apologies for the newbie question...

We are running Netbackup 4.5 with calendar based scheduling.
Our Monday-Thursday tapes have a retention of 12 days and are re-used every 2 weeks.
On Fridays we use different tapes with a retention of 27 days (i.e. they are re-used monthly).

Our problem (and from these forums it seems to be a well known one) is that all of the calendar based backup windows have to close before midnight, otherwise the policy inherits the retention period of the tapes of the following day.
e.g. a Thursday night backup which starts in the early hours of Friday morning would inherit its 27 day retention.

There are many posts which suggest moving from calendar based to frequency based backups in order to solve this.

If we defined a frequency based policy with a window of 12 hours (starting at 7pm), would we encounter the same "retention period" problem where backups which start after midnight inherit the retention period of the following day?
Or are frequency backups immune from that?

Many thanks,
Gurnsy

 

[lenski]

Frequency backups are totaly immune. Because you will not have a backup to inherit the retention policy from. The two schedule types use differant methods to workout what should be run, and the retention period is exactly what it says on the tin/policy. The only fly in the ointment is 27 days does mean 648 hours from when the job ran not as some would expect a convenient time like 12 midnight on the 27th day.