PHOTOS ARCHIVE

I need to create as backup a photo archive of several thousand photos.

Could write to CDs though that takes up a lot of CDs at 700MB per CD.
But has the advantage of not putting too many eggs in one basket.

Could write to DVDs though I would have to buy a DVD Writer.
Advantage of reduced storage volume, compared with CDs but if any DVD becomes unreadable for some reason, then that is about 4 GB worth of photos not backed up or accessible.

And there is the choice of simply copying photos to CD or DVD or reducing the volume by forming .dmg disk images.
Is using .dmg any less reliable, when compared with straight copying?
It seems to involve more links in the chain, to compress and then later expand the files.
Though it clearly reduces the storage bulk.

What do others do?

I back up to a couple of external hard drives; one of them is actually a NAS with mirrored drives. If the data really matters I would always keep at least two copies of it (which makes the number of CDs/DVDs needed even more of a problem). I know that hard disks can fail (hence the mirroring and dual copies), but don't think that writeable CDs are going to last forever either. External drives are so cheap nowadays that they are the natural form of backup as far as I am concerned. Sure beats the days of tape!

Back up to two or more dvd's from a different batch. Store them in different places.
Periodically copy them and throw away the old set.

I've got over six thousand photos backed up from over many years. I keep then on two external hard drives and also copy to DVDs. The HDDs and DVDs are kept in two fireproof boxes in different places. I store all my photos in the original camera format, usually JPG + RAW and store them in folders, by month and year.

As stniuk suggests periodically burn replacement DVDs as their lifespan is unknown. I don't throw my older ones away though, keeping them as archives.

Thanks for those good ideas.

I see no one directly mentioned "disk images" in response to my query :
"And there is the choice of simply copying photos to CD or DVD or reducing the volume by forming .dmg disk images."

I did later try creating some disk images of folders, using 'compression', hoping to save space.

But the resultant disk images were little or no smaller than the originals, so that seems a waste of time, for JPG files, at any rate.

I will carry on just copying files in their original JPG format.

As you say, JPEGs are already compressed. RAW files are not, so compression would save space there. But there are probable easier (and more efficient) ways of compression than using image files.

Any backup needs to keep files in an easy to get to format, nothing worse than a 1GB archive of 1000's of things, and the archive is broke. Better to have the images out as individual files and maybe lose one or two to an error.

Anyone know what the lifespan of files on USB keys is like?