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I have multiple 2-3TB drives inside and connected to my working PC. The data I want to backup on each system lies in the folder "digitalized" (photos, time-lapse, etc).

I have a NAS (PC with 8 drives in a JBOD array) with 9TB free.

I would like to mirror each of my source drives to my backup PC:

d:\digitalized -> b:\
e:\digitalized -> b:\
f:\digitalized -> b:\
g:\digitalized -> b:\
h:\digitalized -> b:\

I manually copied of all source drives to the NAS (which took about 4 days). Here is a WinDirStat screenshot. (Full-size here: - 2 million baby jpegs, eeeeeh!)

Now, one month later, a lot has been deleted, edited and added on the source drives so I need to synchronize everything.

I also have a kazillion tiny useless catalog preview files (from Lightroom) which I would like to ignore. Here is what I have come up with so far:

robocopy X:\DiGiTaLiZeD B:\ *.* /zb /e /purge /eta /xd *.lrdata /xf *.lrprev

Replace 'X' with each drive letter and repeat. Put into a batch file which runs whenever NAS is pingable.


Each time robocopy runs, /purge sees that 75% of the files located on dest do NOT exist on source (D:) because that data is from E:, F:, etc., so it begins to delete everything else! BAD ROBOCOPY BAD! :(

Any clever ideas? It doesn't have to involve robocopy but I thought it would be the simplest since it's included with Windows.

share|improve this question
When I want to mirror files from one location to another, I use robocopy with the /MIR switch. You can probably exclude your tiny annoying files by simply using the same /xd and /xf switches you already use. Generally: robocopy source destination /MIR /R:1 /W:1 – Dave Lucre May 12 '13 at 22:57
Same problem. BTW /mir is the same as /e + /purge which is what I was doing. – glenneroo May 13 '13 at 0:16
On your B:\ drive, can you instead use B:\FromD\, B:\FromE\ etc? Do all the files NEED to be located together in a single destination? – Dave Lucre May 13 '13 at 2:05
Actually no, but that's a really good point which would probably solve my entire problem, wouldn't it? – glenneroo May 13 '13 at 8:27
If you'd like, I can post that as the answer? – Dave Lucre May 13 '13 at 21:53
up vote 1 down vote accepted

Instead of copying your many source drives to the root directory of B:\, create sub directories (B:\FromD\, B:\FromE\ etc) and use robocopy to mirror each source to the sub directories on the B: drive.

share|improve this answer
Which would mean B:\FromD\images, B:\FromE\images, B:\FromF\images, B:\FromG\images, B:\FromH\images, B:\FromD\videos, B:\FromE\videos, B:\FromF\videos, B:\FromG\videosB:\FromD\misc, B:\FromE\misc, B:\FromF\miscB:\FromD\panoramas, B:\FromE\panoramas and so on. This causes all of the store to become extremely fragmented with related files scattered everywhere. Besides having a backup, the whole point to putting them all in one location is so that they can be organized, sorted, de-duped, and cataloged which this method prevents. – Synetech Sep 4 '13 at 19:44
I absolutely agree, but since my own intention is solely to make a backup of my drives, this solution fits. It also has the advantage that if I lose a drive, I can easily find out which files (and directories) were affected. – glenneroo Sep 4 '13 at 21:12

Lose the /purge operation. Its checking each source each time. Run either a separate copy pass with the purge option or simply delete the files with another . line.

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