hazwing wrote in post #15313805
Thanks for the advice, exactly want I wanted to know. I was probably using the wrong terms by saying export.
Yeah, it's good to get those "terms" straight so that we are all talking about the same thing!
So a preview and thumbnail image still remains in the LR catalogue even when the hard drive is disconnected? Do the previews use up much space on the hard drive?
You can see how much space your previews take up by looking in your catalog folder (you can locate it using Edit/Catalog Settings and the location will show up in the opening tab dialog box). Go to that location and and you will see both a .lrcat file (your catalog/database file) and a Previews.lrdata folder for your catalog. You can see the folder size by viewing the Properties for the folder, 'course you can poke around in the folder for seeing the details. My Previews folder takes up a bit over 27 GB, not a hugh amount, but I do keep my catalog on an internal drive seperate from my "system" drive. Some folks prefer to keep theirs on an external drive. I have LR set to delete previews after 30 days.
Another thing that can use drive space is the Camera Raw Cache -- it holds your "1:1" previews (as used in the Develop module). You can view its location, purge it, or set a size limit in the Edit/Preferences/File Handling dialog. Don't set a tiny size though or it will slow down your performance...
Another question though. If I want to backup the files saved on the external drive, whats the best way of doing this? Can I just copy the files from one external drive to the the back-up external drive?
Lightroom backs up the catalog, but not the actual images. So, as you speculated, use your system to copy the images to a backup drive..
If you do have to revert to the backup drive, Lightroom is quite "smart" about "finding" them, as long as you keep the file/folder structure the same as much as possible.