I have seen (but would have GREAT difficulty replicating) a backup tape rotation scheme that evenly (give or take a few writes here and there) utilised 14 (I think it was, maybe 17) tapes over the year, with specific tapes over the cycle enabling rollback to comprehensive historical timeframes.
The result was it was possible to restore previous 5 days along with a number of weeks, then a number of months ending the year with a yearly tape. It worked to keep recent backups longer and gradually decreasing history over longer term and those histories were rotated back into use. It did require that during the cycle a few (3 or 4 I think) would get swapped between themselves to ensure the historical restore options were there. Ie; One day should have Tape 12 according to the series, but the tape needed became Tape 5 to reorient the series (I think!) I lost the spreadsheet that gave the rotation scheme, and I remember thinking you would struggle if you missed a particularly important backup (eg; a monthly) as it might put your scheme out of whack, and restoring would be a slightly more difficult experience as you would have to locate and confirm the correct tape number as the sequence was not 1, 2, 3...7,8 but more like 1,6,3,11,.... But in terms of minimising tape numbers and maximising (even) wear it was pretty impressive. Anyone seen anything like that they can explain better than I have? Anyone up for the maths challenge to come up with it again?!?! -----Original Message----- From: Ben Scott [mailto:mailvor...@gmail.com] Sent: Thursday, 25 March 2010 2:07 PM To: NT System Admin Issues Subject: Re: NTbackup Methods <snip> "We do a simple "grandfather/father/son" rotation. Four daily tapes, MON - THR, which get overwritten weekly. Four Friday tapes, WK2 - WK5, overwritten monthly. Eleven monthly tapes, JAN - NOV, overwritten yearly, run on the first Friday of each month. Every year at the end of December, we run a tape which becomes a permanent archive, never overwritten. This gives us staggered granularity to recover from "I just realized I need a file I overwrote last month"." <snip> ~ Finally, powerful endpoint security that ISN'T a resource hog! ~ ~ <http://www.sunbeltsoftware.com/Business/VIPRE-Enterprise/> ~
