On Tue, 28 Apr 2009, Richard Elling wrote:
I suppose if you could freeze the media to 0K, then it would not decay. But that isn't the world I live in :-). There is a whole Journal devoted to things magnetic, with lots of studies of interesting compounds. But from a practical perspective, it is worth noting that some magnetic tapes have a rated shelf life of 8-10 years while enterprise-class backup tapes are only rated at 30 years. Most disks have an expected operational life of 5 years or so. As Tim notes, it is a good idea to plan for migrating important data to newer devices over time.
I am definitely a fan of migrating data. As far as media degredation goes, perhaps much of the concern is the stability of the base stock (e.g. plastic) or disk drive mechanism and heads, and not the ability of the magnetic stuff to maintain its magnetism.
However, even the planet earth has an average shelf-life of 10,000 years, after which the poles may suddenly be reversed (compass points in opposite direction).
Bob -- Bob Friesenhahn bfrie...@simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/ GraphicsMagick Maintainer, http://www.GraphicsMagick.org/ _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
