Probably no hard and fast answer to this one, hence IMHO.
I’ve finally decided to Do The Right Thing and start keeping a back up data that would be hard/impossible to replace (carefully tagged music files and raw digital photo files.) So I’ve got a nice shiny external (USB2) hard drive and, assuming it plays nice with my linux box, wil copy my data to it then keep it in a different location. I reckon I’ll need to update about once a month, but what else do I need to do? Should I test the data each month by restoring it, or just running fsck? Should I copy the files as they are, or tar them up, or do some clever disc imaging thing? Is one particular filesystem best for long-term storage?
These questions might be better asked on a more specific message board, but I thought I’d turn to the 'dopers as my first port of call.
If the data is really valuable, I recommend multiple backups; maybe burn one copy to DVD and deposit it somewhere off site, to give you a fallback position should you experience loss of the regular backup and the original.
Shouldn’t be necessary to test it by restoring, if you use rsync to back it up, but it wouldn’t hurt to play safe and test it anyway (restoring into a different directory, or onto a different machine - don’t want to overwrite good files with a corrupt backup).
Regarding backups on optical media - the current recommendation continues to be to use “-R” record-once media as opposed to re-writable “-RW” discs.
Supposedly, the dyes in record-once media are more stable and should last longer, and it’s impossible to accidentally or intentionally change or erase.
I’d advise against wrapping things up in gzip, tar or whatever. Images (ie: jpg and gif) are already compressed and attempting to compress already-compressed data only wastes your time. Also, the more you mess with files, more opportunities for data corruption arise.
I wouldn’t quite say that. While JPEGs and GIFs are already compressed, one can sometimes squeeze a few more bytes out by compressing them further. In most cases though, I agree that this would not make a significant difference.
More importantly though, there are other image formats which are not compressed. Bitmaps and uncompressed TIFFs come to mind, as do some PNG files.
Thanks for the replies guys. The images I’m looking to store are in canon .crw raw format, which are already compressed to some extent, and the music files are -q 9 .oggs.
Due to the fact that my computer is about three years old now, the external disk I’m buying has about twice the capacity of my computer’s hard drive, so I’m not too worried about space.
I might take up the option of burning a copy to DVD-R (i.e. get/pay someone to do it for me) for the sake of an extra backup.