Skip to main content

GFS (Grandfather-Father-Son) - Keeping Daily Backup Count

Thread needs solution

I created a GFS backup task where I backup Thursday through Monday, with Monday as the Weekly/Monthly backup day.

I configured to keep 15 days of Daily backups and 8 weeks of Weekly backups. So I was expecting 15 incremental backups to be available. However, after 4 weeks, there are only 8 incrementals. Yesterday there were 12 incrementals but the oldest 4 were deleted after today's monthly backup.

I have attached what the vault looks like.

Is there a bug in the software or am I not understanding what "Keep 15 days" really means?

Attachment Size
gfs_01.jpg 43.63 KB
0 Users found this helpful

Hi Bruce!

This is an expected behavior, that after 4 weeks you have only 8 incremental backups.

From Thursday till Sunday you get 4 incremental backups. The agent checks archive using retention rules - nothing can be deleted now (15 days haven't passed yet).

Next week you get next 4 incremental backups. On Monday after creating the full backup the agent checks retention rules. All 8 incremental backups are still not older than 15 days.

On the third week the fist incremental backup chain (4 backups) will be deleted.

Thank you.

Hi Natalia!

Ahh... "Keep 15 days" means the number of calendar days to elapse before deletions occur...

Now I get it... If I wanted 15 days of Incrementals (and I can actually include the end of week Differentials), I should specify Keep 21 (or maybe 22) days of Daily backups.

Thank you for the clarification!

Bruce

Hi Bruce!

I am glad, that I could help you. In this article you can find the description of the scheme.

Additionaly ou can find there several examples.

Have a nice day!

Hi Natalia,

I have looked at that help information (several times in fact) and I had it stuck in my mind that the Daily backup of 15 "DAYS" translated into number of incremental files.

I probably glanced at the "Work Schedule" example with Daily set to 6 Months but never made the connection that it meant "calendar" "DAYS". Perhaps if I experimented with Daily set to X Weeks or Months that I would have figured it out. But since I didn't want Daily backup for Months at a time, I probably didn't give the example much thought.

Regards,

Bruce