Talk:Grandfather-father-son backup
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There is a lot of confusion about this subject. I find many references that explain the Grandfather-Father-Son rotation schedule as follows:
1 Tape (/set) used for Grandfather = Full Backup
4 Tapes for daily incremental backups Monday to Thursday
1 Tape used weekly on Fridays = Father = Differential backup
My references[1][2] then explain that Full and incremental backups clears the archive bit and that differential backups does not do this. Surely this means that every weekly Differential backup will only contain data that was changed on the Friday and the rest of the weeks info will be lost when those son tapes are re-used again! Or is there another method other than the archive bit used to determine the backup status for differential backups.
If on the other hand weekly incremental backups are made and daily differentials as some references suggest it would mean that more than one father tape would be required for a months worth of backups (i.e. not six tapes but 4+4+1)
- ^ A+ fifth edition, Charles J Brooks, Que Certification, ISBN 0-7897-3044-8
- ^ A+ Certification Concepts & Practice, Charles J Brooks, Prentice Hall, ISBN 0-13-114772-2
After reviewing several online references dating back to 2001, I felt that the simple description was appropriate. Pdinhofer (talk) 19:00, 3 February 2008 (UTC)
