Backups very slow on USB 3.0

Discussion in 'MacBook Pro' started by teejaysyke, Nov 7, 2017.

  1. teejaysyke macrumors regular

    Joined:
    Aug 5, 2012
    #1
    I have the 2015 15" Macbook Pro and a Western Digital Elements 1TB external drie and now my Time Machine backups go so freaking slow it's ridiculous. It used to jump hundreds of MB every few seconds, now it goes 255.4 to 255.7 to 256.1 to 256.8 all the time and takes years.

    Is there something I can do to get maximum speed because this is very annoying and I don't know why I'm getting such slow backup speeds over USB 3.0? (both devices are rated for it)
     
  2. jackiez macrumors newbie

    Joined:
    Sep 16, 2012
    #2
    same thing happened to me few days ago when i am trying to do backup, found this solution and it works like charm.
    just cpu being throttled ( get pretty high usage during the process )

    to speed up time machine

    sudo sysctl debug.lowpri_throttle_enabled=0

    to revert to normal

    sudo sysctl debug.lowpri_throttle_enabled=1
     
  3. teejaysyke thread starter macrumors regular

    Joined:
    Aug 5, 2012
    #3
    I found that if I shut all applications and turned wifi off, the speeds increased dramatically, but once I turned it back on and opened apps it slowed. So I just left it alone with everything off. Would that solution still work?
     
  4. Mlrollin91 macrumors G5

    Mlrollin91

    Joined:
    Nov 20, 2008
    Location:
    Ventura County
    #4
    I've noticed that there are specific parts of the backup that are very slow, but others are fast. The first 5GB seems to move at a snails pace, as with the middle portion for a little bit. Everything else moves rather quickly. My 200GB backup on my iMac takes about 40 minutes.
     
  5. jerryk macrumors 601

    Joined:
    Nov 3, 2011
    Location:
    SF Bay Area
    #5
    At the beginning it needs to locate the files to backup, create space for the backup, and do other prep steps before it can actually start transferring data. That is likely why you see the beginning going slower.
     
  6. Mlrollin91 macrumors G5

    Mlrollin91

    Joined:
    Nov 20, 2008
    Location:
    Ventura County
    #6
    I figured as much, but I found it weird near the halfway point it dropped down in speed considerably for about 10GB Then after that it jumped back up. I don't recall the middle speed drop in Sierra, but I could be wrong.
     
  7. jerryk macrumors 601

    Joined:
    Nov 3, 2011
    Location:
    SF Bay Area
    #7
    I wonder if Time Machine creates some sort of save/restore checkpoints. So that if the user powers off it can pick back up easier. No idea if that is true, but it is something I would design in if they asked me.:) Not that anyone is asking.
     
  8. teejaysyke thread starter macrumors regular

    Joined:
    Aug 5, 2012
    #8
    Once WiFi was off, everything in the beginning, middle, end was BLAZING, the second it was turned back on it dropped to snails pace.
     
  9. jackiez macrumors newbie

    Joined:
    Sep 16, 2012
    #9
    j.
    i am not sure, before i found that solution i tried restart before backing up but still it moved like snail, i do notice that there were few stages where the speed went up and down, still only few mbps or even less

    with that command it speed up to 'normal' speed which is 30mbps +, backup completed in less than 30 minutes.
     
  10. Fishrrman macrumors P6

    Fishrrman

    Joined:
    Feb 20, 2009
    #10
    OP:

    Are you connecting DIRECTLY to the backup drive, or -- are you connecting through a "dock" or hub?
     
  11. teejaysyke thread starter macrumors regular

    Joined:
    Aug 5, 2012
    #11
    Straight from the drive to the Macbook
     
  12. jerryk macrumors 601

    Joined:
    Nov 3, 2011
    Location:
    SF Bay Area
    #12
    Did you disable the lower priority throttling with sudo sysctl debug.lowpri_throttle_enabled=0 as suggested above?

    If not, a dameon or other process may be running at a higher priority doing Wifi related tasks like looking for new WiFi networks, etc. And as a result, Time Machine is not getting cycles.
     
  13. Fishrrman macrumors P6

    Fishrrman

    Joined:
    Feb 20, 2009
    #13
    A suggestion (not one you were asking for).

    Get another external drive.
    Download either CarbonCopyCloner or SuperDuper (both are free to download and use for 30 days).
    Try creating a bootable cloned backup.
    Then... try "incremental updates" over a few days.
    How do things go?

    If you don't like the cloned backup, just erase it and use the drive for something else...
     
  14. ZapNZs macrumors 68020

    ZapNZs

    Joined:
    Jan 23, 2017
    #14
    Have you ruled out drive failure, a near full disk, and directory corruption as possible causes?
    Have you already tried booting into Safe Mode?
     
  15. ActionableMango macrumors G3

    ActionableMango

    Joined:
    Sep 21, 2010
    #15
    Well that's interesting. Can you do an experiment? Download free Blackmagic disk bench. Then run the bench for the external drive with WiFi on and then again with WiFi off.
     
  16. Miltz macrumors 6502a

    Joined:
    Sep 6, 2013
    Location:
    New York
    #16
    Your external HD is very slow and barely makes use of USB 3.0. It's a mobile 5400RPM drive so don't expect much, especially as it fills up.
     

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15 November 7, 2017