G'day guys I've spent many hours with pencil and paper, I certain, but am asking in case someone older-n-wiser can offer sage words:
If I want to backup a system for n days, and be able to recover any particular days files the only way that I can see is to have a daily backup for n days. Tower of Hanoi (for eg) says you can backup 2^^n-1 days with n tapes but i can break that. Simple EG starting with day 4 sequence ie backup: C A B A C A B A (http://en.wikipedia.org/wiki/Backup_rotation_scheme) On day 2 you create a file, which you remove on day 3. On day 6 you try to restore day 2 .... On day 6 you have: A from day 5 B from day 2 (or worse from day 6) C from day 4 So the file created on day 2 backed up on day 3 is lost. Can anybody point to the boat (I've missed) or confirm my vision. Thanks James -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
