Lightroom and/or back-up ignorance ...

I use Lightroom and I back up the file 'My Pictures' on the C drive to a 2TB hard disk (mapped as drive E). I today clicked on one of the DNG files within E, instructing it to open in Lightroom, which it obediently did. But it was the file in its RAWest state - ie without any Lightroom corrections applied subsequent to capture. That, of course, is infinitely better than nothing ... but what file/s should I additionally be backing up to ensure that in the event of actually needing to use my E drive to rescue my photographs, I don't have to process them all from scratch? I know the Lightroom changes are non-destructive, but they should be lurking somewhere(?).

Does that make sense? I can well believe I've misunderstood something rather fundamental about the way Lightroom works or about the back-up process.

I'd welcome advice.

LR should ask you each week about backing up - mine does. The directory you want to hang onto is the one that you export your post-LR files to - I've kept mine as the default "untitled export". This, the catalog and the RAW files are all contained in a RAID array.

Ah, you may have uncovered poor practice on my part. I only export my post-LR files if I need to make a jpeg for (eg) this website ... and since they are invariably lowish resolution for web use, I tend to ditch them after use.

What I think of as the 'real' files remain in 'My Pictures'. The Lightroom catalogue does back-up regularly, but to a separate folder of its own. I also have a further folder: Lightroom 3 Catalog Previews.lrdata.

I suspect this is a bit of a cat's cradle, but if I back up the RAW files, the LR back-up catalogue, and the LR Previews folder will I then have what I need to resurrect LR's content in the event of hard-drive failure?

In theory you should only need the catalogue for LR to function post-catastrophe, so making a backup of that is pretty much a day-1 practice but;

1. I've never put it to the test and
2. I back up everything in the chain, so all I have to restore is the LR shell program then import the catalogue back in to put me where I was. I know that is probably going too far for most people, though.

LR including storage and backups was discussed recently, have a read through this thread.

Thanks both of you: very helpful.

Chris