I used Robocopy to initially populate my ReadyNAS NV from a windows XP workstation. The total copy size was around 30 GB and I was very happy at the copy performance over my 100MB lan (much faster than the Drag-n-drop method).I was happy until I repeated the identical robocopy command only a few minutes later... I noticed that a bunch of files got copied again. Since these had already been copied over once, they should not have been copied the second time.I finally found that using the FFT option solved my problems. Using the FFT option tells Robocopy to assume FAT File Times (2-second granularity). After adding this option, I had no files recognized as 'newer' or 'older' that required re-synching on the ReadyNAS.So now I always use this:Robocopy \\source \\destination /e /z /fftLinks for Robocopy:http://desktopengineer.com/story_20040426101005321?op=makePrintable&styleId=1010http://www.ss64.com/nt/robocopy.htmlRequires subscription:http://emea.windowsitpro.com/Windows/Article/ArticleID/44324/44324.htmlSnippet from http://www.screamingjungle.com/mt2/files/robocopy.pdfSome third-party operating systems declare that their volumes are NTFS, but only implement FAT-style file times with a 2-second granularity. When copying to such a destination from a true NTFS volume, file time rounding may occur, along with unnecessary copying of file data in subsequent jobs. If you encounter this situation, you can use the /FFT (FAT File Times) switch to tell Robocopy to consider file times to be identical if they are within 2 seconds of each other, even though both source and destination appear to be NTFS. This eliminates unnecessary copying in this scenario.Hope this helps ease someone else's frustration in the future...-Brian

Could this be linked to the copying of unmodified files with the backup scheduler in the ReadyNAS 600 ( to an external USB drive ) ?Thanks for an answerGino

In my particular situation, this was a brand new ReadyNAS with no backups configured. This robocopy job was the first time I had put any files on the NAS. Also, I do not yet have an external USB drive hooked up.FYI, I also have a Linksys NSLU2 "NAS" with an external USB drive. I ran into this exact same problem last year with this setup but was not able to find out the FFT solution.

I agree, great tip.I just installed my NV and I was using RoboCopy to sync data from my SATA RAID5 device to my NV. I would have had the FFT problem on my next sync!Enhancement request: Any chance the NV's filesystem could support high resolution (NTFS) timestamps?RegardsPieter

I ran into the same issue.That would be a good addition but I have a feeling that since the underlying file system is ext2/ext3 it will prevent having the same type of file timestamps that are supportd by NTFS. The standard ext2/ext3 inode has 3 time fields, last inode change, last file data change and deletion time. These timestamp fields have a resolution of 1 second. The only time field that maps from NTFS to ext2/ext3 is the file data modification time.So, I would think that the underlying filesystem would have to be changed to allow for the timestamp compatability with NTFS.

brianadkins

Tutor

Apr 26, 2006

Robocopy

I used Robocopy to initially populate my ReadyNAS NV from a windows XP workstation. The total copy size was around 30 GB and I was very happy at the copy performance over my 100MB lan (much faster than the Drag-n-drop method).

I was happy until I repeated the identical robocopy command only a few minutes later... I noticed that a bunch of files got copied again. Since these had already been copied over once, they should not have been copied the second time.

I finally found that using the FFT option solved my problems. Using the FFT option tells Robocopy to assume FAT File Times (2-second granularity). After adding this option, I had no files recognized as 'newer' or 'older' that required re-synching on the ReadyNAS.

So now I always use this:
Robocopy \\source \\destination /e /z /fft

Links for Robocopy:
http://desktopengineer.com/story_20040426101005321?op=makePrintable&styleId=1010
http://www.ss64.com/nt/robocopy.html

Requires subscription:
http://emea.windowsitpro.com/Windows/Article/ArticleID/44324/44324.html

Snippet from http://www.screamingjungle.com/mt2/files/robocopy.pdf
Some third-party operating systems declare that their volumes are NTFS, but only implement FAT-style file times with a 2-second granularity. When copying to such a destination from a true NTFS volume, file time rounding may occur, along with unnecessary copying of file data in subsequent jobs. If you encounter this situation, you can use the /FFT (FAT File Times) switch to tell Robocopy to consider file times to be identical if they are within 2 seconds of each other, even though both source and destination appear to be NTFS. This eliminates unnecessary copying in this scenario.

Hope this helps ease someone else's frustration in the future...

-Brian

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