Compare two disks: DeltaWalker slow?

Discussion in 'Mac Apps and Mac App Store' started by Canubis, Dec 27, 2015.

  1. Canubis, Dec 27, 2015
    Last edited: Dec 27, 2015

    Canubis macrumors regular

    Canubis

    Joined:
    Oct 22, 2008
    Location:
    Vienna, Austria
    #1
    I am trying to compare two SSDs (one external via USB 3.0 the other internal in MacBook Air 2011) with DeltaWalker to see if anything changed in the external one. External one is 240GB and nearly full. The other one is 480GB and by around 90% full. DeltaWalker already runs for about 20 hours, according to Activity Monitor it is not responding from time to time but then the UI of DeltaWalker seems to get updated every few seconds (spinning wheel moving). Is it normal that a compare of two disks takes that long? How much longer can it take? Any experience?


    (Background Story: the external disk used to be my internal one some time ago. So all data on external disk should also be on the internal one. SHOULD… :D I'd like to delete this old version of my startup disk and use it for other purpose as I either way have other backups. But before I do so I'd like to make sure I really have all the data on my new disk and don't forget a file…)
     
  2. slayerizer macrumors 6502a

    slayerizer

    Joined:
    Nov 9, 2012
    Location:
    Canada
    #2
    You could do a RSYNC between the two, with the -n switch (which is the dry-run testing mode).

    Code:
    rsync -arn SRC DEST
    this will tell you files that are on the source and not the destination (without copying anything).

    If you want to know which files are on the DEST but not on the SOURCE
    Code:
    rsync -arn --delete SRC DEST
    you don't need to scan the full disk if you don't want. And you can also exclude folders from the scan which would make it faster.

    fast, free and reliable!
     
  3. simonsi macrumors 601

    simonsi

    Joined:
    Jan 3, 2014
    Location:
    Auckland
    #3
    Did you originally copy all of the 240GB drive onto the 480GB? Might be better to run CCC to clone the 240GB to the 480GB but set it to "preserve newer files"...
     
  4. Canubis thread starter macrumors regular

    Canubis

    Joined:
    Oct 22, 2008
    Location:
    Vienna, Austria
    #4
    Sorry for the late reply. I was so busy over the past weeks and somehow forgot about asking this questions actually. So thank you for your kind reply. However, I just tried what you suggested, in fact with some testing environment with just two folders and 3 files insider folder 1, of which I copied over only two files to folder 2. Did a quick rsync as you suggested above and rsync doesn't seem to do anything. Weird, isn't it. Even with verbose, the output seems kinda meaningless, isn't it? Did I do anything wrong?

    [​IMG]
     
  5. MacUser2525 macrumors 68000

    MacUser2525

    Joined:
    Mar 17, 2007
    Location:
    Canada
    #5
    A rsync -avP folder1/* folder2/ will sync the two. If wanting to get rid of the files present on the target folder/drive and not on the source then you add a --delete to the command, to test what will happen before letting it do it a --dry-run should be added then removed when happy it will do what you want.
     
  6. Canubis thread starter macrumors regular

    Canubis

    Joined:
    Oct 22, 2008
    Location:
    Vienna, Austria
    #6
    Thanks! The problems seems to have been with missing the slashes after the folder names to sync between. The following command seems to do exactly what I wanted: get a list of files that are in folder 1 but not in folder 2:
    Code:
    rsync -arnv folder1/ folder2/
    Note: without the -v switch for verbose mode there is no output at all. So this seems to be needed to get any feedback in dry-mode… maybe there are other ways, but at least for me this is now doing the job. Thanks everyone being involved for your kind support and suggesting this alternative to DeltaWalker.
     
  7. MacUser2525 macrumors 68000

    MacUser2525

    Joined:
    Mar 17, 2007
    Location:
    Canada
    #7
    If you do not want trailing slash on source then this works rsync -avP path/to/source/folder /path/to/destination/. This tells it to archive verbosely if interrupted progress resume where copy left off ie. do not start last file it was syncing from the beginning. The folder names on the source and destination need to be identical as it will be syncing just the folder and its contents on the source with the identical one on the destination.
     

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