Digital archiving tools

On Sat, Mar 12, 2011 at 02:53:54PM -0500, Teo Zenios wrote: *eek* DDS tapes are _not_ a reliable backup medium, quite the opposite, they can be a perfectly valid excuse why some annoying data has be "lost". In a previous job, we used DDS3 tapes for boot & install (Ignite-UX tapes). We always kept three copies of each tape and despite rarely using them (well, how often do you reinstall a Unix production or even staging server?) and the low machine count (IIRC < 10 machines) I aquired a stack of 10 or 15 dead (== read errors) tapes in 2 years in that job. As a contrast, the SDLT library had some 20 or so tapes in it, with regular use (it being _the_ backup storage system) and it rejected (due to read errors IIRC < 5 tapes in that same time. In fact, from what I've seen, DDS tapes should be considered suspect after 10-20 cycles (load/unload/read/write) and considered junk after 30-40 cycles. Plus there is the charming habit of some HP DDS drives to very slowly drift out of alignment. So you can read the current and last few generations of backup tapes on that drive but should it ever die ... My MO drive unfortunately died, so I'm on the (low priority) lookout for a replacement. But these days, my backups go either onto DLT-III(XT) (10/15 GB native) or LTO1 (100 GB native) backup tapes. Both are linear recording (as opposed to the helical recording of DDS) tape systems and both are specced to keep their data intact for 20+ years and 500+ cycles given proper storage. Another backup medium I use is DVD-RAM, which sounds reasonably promising as a backup storage medium, plus you can put a filesystem on it and run r/w operations, simplifying access. Kind regards, Alex. -- "Opportunity is missed by most people because it is dressed in overalls and looks like work." -- Thomas A. Edison