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Grandfather-Father-Son backup rotation?

Created: 23 Mar 2006 • Updated: 06 Aug 2010 | 4 comments

I have some questions about Grandfather-Father-Son backup rotation and Media sets.

I have 20 backup tapes, Symantec Backup exec 10d, Dell power edge server with Windows 2003 server. My backup device is Tandberg TS400 (PV110T Lto2).

No backups on Saturdays and Sundays.

How should I set op my GFS backup rotation scheme? First I thought of this, but some months have more than 4 Fridays.

Monday (incremental)
Tuesday (incremental)
Wednesday (incremental)
Thursday (incremental)

Friday1 (full)
Friday2 (full)
Friday3 (full)

And on the fourth Friday run my monthly backup

January
February
March
April
May
June
July
August
September
October
November
December

I am really lost :/
I have checked the policy that comes with the program and copied it and try to change the different templates.
And my second question is about media sets. Should I have three media sets? One for daily, one for weekly and one for monthly?
I change backup tape every day.

/anneli

Comments 4 CommentsJump to latest comment

ray littlefield 2's picture

Change your monthly backup to the 1st Friday of each month.

Weekly backups can occur on 2nd, 3rd, 4th, & last friday of each month.


'Should you have three media sets?' A general answer would be 'yes' for a GFS rotation. Keep in mind, rotation sets are really for defining how long you want to perserve the data. So ideally your Monthly backup media set has a very long overwrite protection period (months or years), your weekly media set OPP would be less (Weeks or months) and your daily set would be even less (days or weeks).

However, in your initial post you indicated you have 20 tapes, and you change tapes everyday. On average there are 20 weekdays in a month, so every month you would rotate through your entire set of tapes. -I'm not sure a GFS rotation is required for something like that.
However, if you changed tapes at the beginning of the week for the incremental jobs, and left that tape in all week, then changed it Friday for the weekly/monthly job, you would use only ~ 8 tapes a month, and that would give you more retention, and more justification for a GFS rotation.

Anneli Hultberg's picture

Thanks for your answer.

To see if I understand things right, here is what I plan to do now.

Daily Template Settings:
Incremental
Weekdays
1st Mon Tue Wed Thu
2nd Mon Tue Wed Thu
3rd Mon Tue Wed Thu
4th Mon Tue Wed Thu
Last Mon Tue Wed Thu

Weekly Template settings
Full
Weekdays
2nd Fri
3rd Fri
4th Fri
Last Fri

Monthly Template settings
Full
1st Fri


And then I wonder about the setting (under each template)
"When this job begins"
Should I Check "Overwrite Media" or leave to settings at "Append to media, overwrite if no appendable media is available".

I will change backup tape everyday, so I will not leave one in the whole week (Mon-Thu).

I still am I bit confused about the media set settings

Media set 1 Settings
Daily (meaning 4 tapes named Mon, Tue, Wed and Thu)
Overwrite protection 5 days
Append period 1 day

Media set 2
Weekly (4 tapes named fri1, fri2, fri3 and fri4)
Overwrite protection 15 days
Append period 1 day

Media set 3
Monthly (12 tapes named Jan, Feb etc?.)
Overwrite period 50 weeks
Append period 1 day

Is it ok with the append period setting? Or should I change it to hours?

Shilpa pawar 2's picture

Hi,

Under the Grandfather Strategy you can use minimum 19 tapes effectively for 1 year.
Depending upon your requirements you need to set the Overwrite Protection Period(OPP) and the Append Period(AP) to the media set

For more details on this scheme, you can refer to the following technotes which will give you information about creating a Rotation scheme :

http://seer.support.veritas.com/docs/192265.htm
http://seer.support.veritas.com/docs/237374.htm

NOTE : If we do not receive your reply within two business days, this post would be marked "assumed answered" and would be moved to "answered questions" pool.

csplinter's picture

What do you mean effectively for 1 year? At what intervals? I don't mind reading, but your second link is dead.

I didn't originally configure this server, so don't ask me why, but we have 7 media sets; 5 designated Mon-Fri, 1 monthly, 1 weekly. We also have 7 jobs corresponding to the 7 media sets.

Could you please explain how many media sets and jobs we should have for the grandfather strategy?