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Lightroom Catalog Previews Backup

FredL

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I frequently back up my Lightroom catalog to an external hard drive. Is it necessary to also back up the previews.lrdata and smart previews.lrdata files also?
 
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Not really. They can be recreated if necessary. On the other hand, re-creating them could take a long time if your catalogue is big. To make a decision, you'll need to balance that possible long time with the certain time spent periodically backing up your previews and smart previews (which also involves a fair amount of time if your catalogue is big).

Personally, I don't do it, but my catalogue is relatively small.
 
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If there is room on that external disk, I would advise to do it. Backing up previews takes little time, because the previews 'files' are really folders. Any good backup utility will only backup those previews that are changed, so it won't take more than a few minutes. Rebuilding all the previews on the other hand takes about 1-2 seconds per preview (depending on your computer and the size of the raw files), so you can do the math what that means...
 

FredL

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Thanks Hal & Johan.... my catalog continues to grow, so I will take your advice and back up these preview files/folders (I have a 4T external hard drive, so space won't be a problem).
 

gpsmikey

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Thanks Hal & Johan.... my catalog continues to grow, so I will take your advice and back up these preview files/folders (I have a 4T external hard drive, so space won't be a problem).
Said the man with a 80 meg drive, then a 1 GB drive, then a 8 GB, then a 120GB, then a 500GB, then a 1TB then a 2TB drive back in the day :)
The VERY important thing to remember is disk space is like garage space - doesn't matter how big it is, you will always find "stuff" to fill it so it doesn't suffer from being empty (I have 7 TB spinning behind me right now). :rolleyes:
 

gpsmikey

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On the topic of backing up the previews, one question - the previews in the folder path previews.lrdata those are just a preview of the file without any other information or changes correct? (when I update keywords, develop information etc., it is not going to change the preview if I understand correctly. Only if I import a new file etc. will there be changes in the preview folders is that correct?
 
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On the topic of backing up the previews, one question - the previews in the folder path previews.lrdata those are just a preview of the file without any other information or changes correct? (when I update keywords, develop information etc., it is not going to change the preview if I understand correctly. Only if I import a new file etc. will there be changes in the preview folders is that correct?
It depends.....Smart Previews are never updated after the first creation. Library previews, OTOH, are always being updated if you make any develop-related changes (technically speaking, the current preview file is automatically deleted when you make a develop change, and a new preview file is created).

I don't generally back up my Previews caches, though I guess it would perhaps make sense to back up the Smart Previews. I tend to trash my Library previews cache every time I go through a major version catalog upgrade (the upgrade process "steals" the previews cache from the previous catalog, I think it's better to start afresh with new catalog, new previews). With that in mind, I don't bother backing them up.
 

gpsmikey

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Be nice - I still have a couple of 8" DSDD floppy drives and a box or two of floppies for it downstairs. Wasn't sure how I was going to fill up 1.2 megs of space - who needs more. My first hard drive was 40 megs - my D810 can fill 5 of those a second if I am in the continuous fast mode (raw). I have 96GB of cards in the camera. Like garage space - no matter what you have, you will fill it!!
 

gpsmikey

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Thanks Jim - I was just looking at mine and the previews folder is 110,000 files and 50GB roughly. Took it a day or so to create all those. If it is only develop changes that get reflected in the previews (and not keyword changes etc.), then I guess it would not be too big an impact on my backups (except for the first backup of the previews). I could still go through and work on my keywording etc. and not trigger massive backups across my network to the Linux machine each time (the catalog itself is currently less than 2GB).
 
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Thanks Jim - I was just looking at mine and the previews folder is 110,000 files and 50GB roughly. Took it a day or so to create all those. If it is only develop changes that get reflected in the previews (and not keyword changes etc.), then I guess it would not be too big an impact on my backups (except for the first backup of the previews). I could still go through and work on my keywording etc. and not trigger massive backups across my network to the Linux machine each time (the catalog itself is currently less than 2GB).
Correct. My Lightroom catalog contains about 150,000 images. The previews take about 140 GB. I backup every time I work with Lightroom. After a normal working day (a day without adding new images), making the backup of the catalog and the previews takes less than 5 minutes.
 
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