Migration Assistant - which data transfer method is faster?

Discussion in 'iMac' started by pward, Dec 30, 2015.

  1. pward macrumors member

    Joined:
    Nov 26, 2008
    #1
    Hi,

    I set up my brand new 5K iMac yesterday and used Migration Assistant to restore the Time Machine backup from my previous iMac, a 27" Mid-2010 model. Migrating c.450GB of data took six hours.

    I will be passing on my old iMac to a friend who will need to restore data from their old iMac. They have a Time Machine backup which we could use but would the migration process be quicker if we connected both iMacs together with an Ethernet cable?
     
  2. maflynn Moderator

    maflynn

    Staff Member

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    May 3, 2009
    Location:
    Boston
    #2
    How is the external drive connected to the iMac?

    I'm guessing USB, and as such, I think that USB would be faster then gigabit ethernet, and so it would actually be slower using ethernet, then USB.

    I too found TM to be slow, I would recommend using Carbon Copy Cloner to back up the iMac to an external drive and then use that to restore to the new iMac.

    I've gone the CCC route and it only takes a fraction of time that TM needs.
     
  3. AlliFlowers Contributor

    AlliFlowers

    Joined:
    Jan 1, 2011
    Location:
    L.A. (Lower Alabama)
    #3
    I'd connect them with a thunderbolt connector. Took me no time when I went from my MBP to my MBA. Just used target mode.
     
  4. pward thread starter macrumors member

    Joined:
    Nov 26, 2008
    #4
    Yep, external drive was connected using USB but it was USB 2.0 as that was all my Mid-2010 iMac would support.

    Would USB 2.0 really be faster than Gigabit Ethernet?

    Thanks for the tip on Carbon Copy Cloner.
     
  5. pward thread starter macrumors member

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    Nov 26, 2008
    #5
    Thanks but neither Mac has Thunderbolt...
     
  6. AlliFlowers Contributor

    AlliFlowers

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    Jan 1, 2011
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    L.A. (Lower Alabama)
    #6
    Bummer. :(
     
  7. torquer macrumors regular

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    Oct 16, 2014
    #7
    USB 2.0 is definitely not faster than GigE and honestly USB 3.0 with its overhead likely wouldn't be either. You're going to be limited by the transfer rates of the drives involved either way, but since you're lacking in USB 3 on both machines, definitely go Ethernet. Even with SSDs (except for the very newest Macs with PCI-E speeds), your bandwidth over Gigabit Ethernet will far outstrip the ability of the drives to read/write data.
     
  8. hfg macrumors 68040

    hfg

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    Dec 1, 2006
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    Cedar Rapids, IA. USA
    #8
    Gigabit ethernet really isn't all that fast, as the data transfer rate is only 125MB/s theoretical maximum.

    In real life you may only see 60% - 80% of that speed on a typical home network. At those transfer rates it won't "far outstrip" the R/W data rates of modern disk drive systems or even individual drives, let alone SSDs. USB 3.0 or Thunderbolt would likely provide better data transfer rates if available on both devices.
     
  9. maflynn Moderator

    maflynn

    Staff Member

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    May 3, 2009
    Location:
    Boston
    #9
    I found in my real world usage, that it was. I'd have a NAS connected via ethernet to my Mac, and an external drive to the USB 2.0 port on my MBP. The USB would copy the data faster then it would go over the wire to the NAS
     
  10. terrymaz macrumors regular

    Joined:
    Aug 3, 2010
    Location:
    SF Bay Area and Chicago Area
    #10
    Im waiting on my 27in to arrive. My 12 MBP has only 10gig free of the 512 ssd (went with 1tb ssd for new iMac) My photos take a HUGE amount of it. I kind of want to do a clean start but want things like apps, docs, etc on the new one. Is there a preference selection where it doesn't take 340 gig worth of photos to the new one? Whats so special about Carbon copy? Thanks for any input
     
  11. Weaselboy Moderator

    Weaselboy

    Staff Member

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    Jan 23, 2005
    Location:
    California
    #11
    Yes... if your Photos library is in the default Pictures folder, when you get to this step in the migration, just click the triangle next to your user name and scroll down and uncheck Pictures and that folder will not be migrated.

    iur.png
     
  12. zhaoxin macrumors regular

    Joined:
    Jan 28, 2015
    #12
    To find which kind of way is faster, you should know what happens when the migration is doing.

    For Time Machine to Mac, the files transfer from the backup disk to OS X disk, as the Time Machine contains all the history files, some of the files in the latest backup is marked by links to the old backups. So comparing to direct link between Macs. Time Machine need extra time for this.

    Also, most of the backup files are some files, when read those files, hard drive needs to locate each of them separately. Since the files are very small, comparing to the transfer time, the finding time becomes big. Especially if you transfer them by network, the latency is even bigger.

    Conclusion:
    1 If both side are SSDs, it is the best
    2 Use directly connect if you care the time length most

    I also suggest erase and reinstall the OS X before he does the migration.
     
  13. terrymaz macrumors regular

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    Aug 3, 2010
    Location:
    SF Bay Area and Chicago Area
    #13

    Thanks. I'll have to check. On my MBP everything was being imported directly to Aperture for pics. Im making the switch to Lightroom and photoshop for the iMac though since Apple is no longer supporting Aperture. Grrrr
     
  14. torquer macrumors regular

    Joined:
    Oct 16, 2014
    #14
    The OP stated he was transferring from a 2010 iMac which is limited to either SATA1 or SATA2. Unless they manually upgraded to an SSD (possible but not mentioned), we're dealing with a 5400 RPM disk drive most likely with a transfer rate of around 40-50MB/sec. So yes, gigabit would far outstrip that disk transfer rate. Also as a 2010 iMac USB 3.0 isn't available making that not an option. I probably spoke less than artfully because I included the context of the OP's comments.

    Where USB 3.0 is available on both devices and both devices are SSDs on SATA2 or better, it is preferable. Thats not the case here based on the OP's statements though.
     
  15. mmomega macrumors demi-god

    mmomega

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    DFW, TX

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