> From: tech-boun...@lists.lopsa.org [mailto:tech-boun...@lists.lopsa.org] > On Behalf Of Bill Bogstad > > Not sure if my previous (subject only) note made to the list or not, > but the subject line pretty much says it all anyway. Although, it > should not matter for answering my question, my motivation is to > get some idea of the feasibility of treating disk drives the same > way as tape cartridges. i.e. Leaving them on a shelf for extended > periods of time and then expecting to retrieve data from them. > While there have been public studies in recent years on the lifespan > of powered disk drives, I can not find anything other then anecdotal > comments about unpowered drives.
Both posts made it to the list, but I respond to this one because it was later. ;-) I don't know if this helps at all, but I can say this: The longevity of both tapes and off-powered drives and optical media are mainly dependent on chemical deterioration of the material, and nothing lasts forever, and it's highly environment dependent as well. Hard drives are at least sealed, which minimizes environmental factors. If the manufacturers don't include specific processes and controls to achieve a design spec, you just never know what you're going to get. The best you can rely on is historical statistics, which may or may not be good indicators of future performance (not to mention, may or may not be well studied and have readily available published statistics.) So my actual comment is this: I have had tapes go bad. I have had optical media go bad. That is - numerous tapes, and numerous burned DVD's. In all cases, we were able to recover only because backups had been archived regularly, so we were able to recover the necessary information from the previous or subsequent weeks' or months' backups. It was only later that I started using hard drives as archival media - and adopted the habit of making every backup redundant, and performing regular media validation as well. Given that all media types can and do deteriorate and fail, the only way to get reliable backups offline is to have multiple redundant archives, and actively validate. The process that I *actually* follow is to have a server with removable media bays, and purchase sufficient media to populate those bays and also have sufficient offline archives offsite. Periodically (weekly) rotate one media set offsite, while bringing another back for validation. Unfortunately I don't have performance statistics for hard drive media... Which is what I think you're actually seeking... _______________________________________________ Tech mailing list Tech@lists.lopsa.org https://lists.lopsa.org/cgi-bin/mailman/listinfo/tech This list provided by the League of Professional System Administrators http://lopsa.org/
