Server + - Grandfather-Father-Son

Author

Grandfather-Father-Son

Sunha

2002-04-05, 10:44 am

Could someone please help. My test is tomorrow. I have a bit of confusion about the Grandfather-Father-Son backup scheme.

According to my understanding at the end of a normal month you would have 4 son tapes 4 father tapes and 1 grandfather. So 9 tapes

At the end of one year you would have 4 son tapes 3 father tapes and 12 monthly tapes. So 19 all together. Is this correct?

Sunha

wbafrank

2002-04-05, 11:04 am

Based on a weekly schedule

The GFS strategy is a method of maintaining backups on a daily, weekly, and monthly basis. GFS backup schemes are based on a seven-day weekly schedule, beginning any day. A full backup is performed at least once a week. All other days, full, partial, or no backups are performed. The daily backups are the Son. The last full backup in the week (the weekly backup) is the Father. The last full backup of the month (the monthly backup) is the Grandfather.

By default, you can re-use daily media after six days. Weekly media can be overwritten after five weeks have passed since it was last written to. Monthly media are saved throughout the year. These can and should be taken off-site for storage. You can change any of these media rotation defaults to suit your particular environment.

Sunha

2002-04-05, 12:05 pm

Thank you wbafrank,

Would you please check my arithmatic.

If you did a GFS backup from monday to friday. you would then have 19 tapes on December 31. But if you did a GFS backup from Mon-Sat you would have 20. But if a month has 5 Saturdays how many tapes would you have?

I am sorry. I realize how insignificant this question seems, but before an exam I am always very nervous and Exam Drill has only one scenario with 19 tapes on December 31.

Thank you in advance.

wbafrank

2002-04-05, 4:38 pm

Have a look a the attached examples:

http://www.amaonline.com/dlps/Backup_rotation.htm

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