On Wed, 2010-03-24 at 15:09 -0500, Marcio Vogel Merlone dos Santos wrote: > What is the best strategy and storage media for long-term backups, > say > to 10 or 20 years (if any)? I ask because I do have an old DLT tape > drive and some tapes, unusable, because its SCSI controller is no > longer > among us. It is not 10 years old and is already a problem.
There's really not a single best answer to this, in my opinion. Long-term archiving is a complex, multi-faceted problem, and solving this problem is an IT discipline unto itself and not my personal specialty. What *I* prefer to do -- though YMMV, and archival specialists probably think I'm nuts -- is to keep my backups on live media such as hard drives rather than traditional removable media. But I maintain and upgrade that live media with each technology generation. In other words, I don't try to make a single medium last for more than 3-5 years. This works well for my situation of a couple terabytes, with today's drives, but it doesn't scale to a large enterprise where data is counted in exabytes. We back up to an "octopus" of 1 TB USB drives and rotate drives off-site. We're about to implement redundant octopi so that we have at least two copies of everything, and we these will be at two different data centers. iSCSI offers some interesting options for building this kind of solution. You can also use offline media but be selective about what standards you choose. Tapes that are peculiar to one manufacturer and model of drive are a bad long-term choice, but something that is a multi-sourced industry standard is likely to be readable further into the future. Take floppy disks, for example -- way past obsolete, and hardly anyone has an old-fashioned Intel 8272 style FDD controller. But you can still buy USB 3.5" floppy drives even though USB wasn't even invented when floppies were current technology. I would predict that CDROM and DVDROM media will be similarly long-lived in that you will be able to buy readers for them far into the future. These also have the advantage of their format being ISO 9660 standard. But their capacity is very limited. The jury is still out on Blu-Ray media's long-term archival stability. The other thing to consider with archiving is the internal file format of your data. Try to read a document from Microsoft Word 2.0 today and see how much of it is comprehensible to modern versions. I recommend spinning out proprietary formats into PDF or RTF or plain text versions -- again, something that is a published standard -- alongside the vendor-specific format, so that in the future even if you can't read the original you are still likely to be able to retrieve the basics from the less-rich but more standardized open format. Programs like "antiword" (which is Open Source) can automate some of the export process, albeit with some loss of formatting. That's why you keep both the original and the exported copy -- the copy is your "last resort" if you can't read the rich-format original. In other words, you could have the best archival *media* in the world but still be unable to recover data if you can't read the file format any more. I've seen this aspect ignored a lot. Scott -- ------------------------------------------------------------------------ Scott D. COURTNEY, Principal Engineer Sine Nomine Associates scourt...@sinenomine.net http://www.sinenomine.net/ ------------------------------------------------------------------------------ Download Intel® Parallel Studio Eval Try the new software tools for yourself. Speed compiling, find bugs proactively, and fine-tune applications for parallel performance. See why Intel Parallel Studio got high marks during beta. http://p.sf.net/sfu/intel-sw-dev _______________________________________________ Bacula-users mailing list Bacula-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bacula-users
