Question about unfusing Fusion Drive

Discussion in 'iMac' started by Delarock, Dec 25, 2016.

  1. Delarock macrumors newbie

    Joined:
    Dec 25, 2016
    #1
    Hallo there, i have imac 5K 2015 with fusion drive 2tb.
    I feel comfortable with disk speed, but i hate the noise of spining hard disk, i thing its overall noisy. My friend have the same configuration with SSD and its far less noisy)
    Iam not heavy user, just wathing few films, office, browsing and my medical programs( now i have 200 gb used from 2tb capacity and half of that are old unusefull files which iam lazy to delete)

    I would like to unfuse the drive, instal system just on internal 120 gb SSD drive a unmount/deactive the spining disk. Is it possible? I found some commands but no one tried it on 5k imac.
    I would like to buy external thunderbolt/ usb SSD disk to use it for data (for downloads, big files ETC)

    Is this fine solution, any hints?
    Thanks in advice, R.
     
  2. maflynn Moderator

    maflynn

    Staff Member

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    Boston
    #2
    You can unmount the drive via the Disk utility but you cannot deactivate it. The hard drive will continue to spin. If you want zero noise coming from the hard drive, you'll have to disconnect the power supply and if you're going to do that, you might as well remove it.
     
  3. Delarock thread starter macrumors newbie

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    Dec 25, 2016
    #3
    Thanks for reply, but are you sure? Even if you unmount it, cancel indexing in spotlight and will use only ssd and sleep mode is on in energy saver?
     
  4. maflynn Moderator

    maflynn

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    #4
    No I'm not, all I can say is, try it and report back.
     
  5. mpe macrumors regular

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    Sep 3, 2010
    #5
    Are you sure that the noise is from HDD and not from the cooling fan?

    I have use iMacs with and without HDD and can't hear any difference unless I place my ear directly on the surface.
     
  6. rayward macrumors 68000

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    Mar 13, 2007
    Location:
    Houston, TX
    #6
    Has to be the cooling fan which, if the heat sensor is broken/missing on the HDD, will cause the fan to run constantly at warp speed.
     
  7. RedlegsFan macrumors 6502

    Joined:
    Mar 15, 2012
    #7
    I have the 2TB fusion drive in my 2015 iMac and notice zero noise. This thing is quiet from my perspective.
     
  8. briloronmacrumo macrumors 6502

    briloronmacrumo

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    Jan 25, 2008
    Location:
    USA
    #8
    Even with all that, the OS still checks on the internal hard drive ( or its logical equivalent ) at boot time. It won't stop boot time access but you can stop it from boot mounting by adding the volume UUID ( available via by using this command )
    Code:
    diskutil list
    to /etc/fstab file using the pico editor in Terminal.app
    --- Post Merged, Dec 27, 2016 ---
    I would check the hard drive with a SMART utility to make sure it isn't failing. Finding the root failure ( others have mentioned fan sensor as a possibility ) is probably the best first step before embarking to defuse. Most Fusion drive users are NOT reporting this noise, so if noise is the only concern I would tackle it first. Once you decide defusing makes sense ( and I'm not sure you're really there yet based on what you posted ), there are more options to consider.
     
  9. Delarock thread starter macrumors newbie

    Joined:
    Dec 25, 2016
    #9
    Thanks for replies guys. I think that there is one subjective problem . Everyone of us has different sensitivity for noise and working condition (noise at room) My fusion is healthy, no fault for sure but i can hear what is noise from fan and what from disk. For example when i wake up computer, first 2 sec just fans start working and then disk spin up, and there is difference.

    Question for those who are mentioned that their fusion is completely silent. Do you hear that sound? ( dont know exact word in english, but when disk is reading somenthing or writing, f.e. opening older files which are not stored at SSD)
     
  10. Fishrrman macrumors G4

    Fishrrman

    Joined:
    Feb 20, 2009
    #10
    You could...

    - DE-fuse the drives
    - Set the SSD up with OS, apps, accounts, smaller libraries
    - Set the HDD up with large libraries and seldom-accessed stuff
    - Set prefs to "spin down unmounted drives"
    - After boot, UNmount the HDD
    (as you mentioned in the original post above)

    I'm thinking that so long as you don't try to access the unmounted HDD, it will stay "spun down" (and quiet).

    However -- keep in mind that the OS has its own reasons for "touching" an unmounted drive (and perhaps spinning it up in the process). This might become annoying.

    You may discover that having the HDD spinning -all the time- is less annoying than having it spin up now and then, and then having to manually unmount it once more...

    Other than that, get earplugs.
     
  11. rayward macrumors 68000

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    Houston, TX
    #11
    My fusion drive is silent. I don't notice any sound at all.
     
  12. maflynn Moderator

    maflynn

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    Boston
    #12
    Same here, I do not hear any drive noise, or any noise for that matter from my iMac. When I push it, and the fans ramp up, there is some sound, but normal usage, its whisper quiet
     
  13. Phil A. Moderator

    Phil A.

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    Shropshire, UK
    #13
    I can hear disk sounds from my fusion drive occasionally but it's quieter than the fan and much quieter than the 6 spinning disks in my NAS that's about 6 feet away from my desk :)
     
  14. varian55zx macrumors 6502a

    varian55zx

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    May 10, 2012
    Location:
    San Francisco
    #14
    I went pure flash, so I'm completely silent.

    I didn't find the 2 tb fusion to be loud, however.
     
  15. Delarock, Jan 3, 2017
    Last edited: Jan 3, 2017

    Delarock thread starter macrumors newbie

    Joined:
    Dec 25, 2016
    #15
    Maflynn what year of imac do you own.

    Maybe my mac is noisy or iam too sensitive for noise. Dont understand how 7200 rpm disc in so thin body can be absolute silent, as mentioned few users there. I listen even spining of disk :D

    I will wait auntil guarantee will end( year and 3 months) and will buy 500 gb from OWC.
     
  16. maflynn Moderator

    maflynn

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    #16
    Its a 2015 iMac, I bought it when it was first introduced.

    My iMac has been and continues to be whisper quiet.
     
  17. tentales macrumors 6502a

    tentales

    Joined:
    Dec 6, 2010
    #17
    Go into Terminal.

    Type "diskutil cs list"
    Look for the long list of characters and numbers to the right of "Logical Volume Group" associated with your Fusion Drive.
    At this point it's advisable to not have any other disks or flash drives attached, to not get confused.
    Then,
    type "diskutil cs delete LVG" where you replace the LVG with the UUID of your unique volume group identifier.
    It will look something like this: "diskutil cs delete 97EFEC8D-80AF-4417-800D-4A8EFF748AF7"

    Make sure not to copy the example I give, as YOUR volume group ID is unique to your machine.

    After this, you Fusion Drive will be broken into HDD and SSD.
    I personally would not recommend this, but it's your machine.

    I'm with the others, that the disk is quite silent, albeit your ears may differ.
    However, I'd get another opinion from a friend, if your HDD noise is excessive, you might have a defective disk or missing damper. Fan noise is typically louder.

    If you have the skill and patience to follow the ifixit HDD replacement slides, by all means, open up your iMac and replace the HDD with a 2nd SSD drive or disconnect it altogether.
     
  18. cbdilger macrumors newbie

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    Oct 15, 2013
    Location:
    West Lafayette, IN
    #18
    OWC is always a good choice. But: this is by no means an easy upgrade and if you open the case your warranty is toast. You need to be absolutely sure it's the drive and not the fan or something else.

    Two suggestions if you persist: (1) Buy the upgrade kit which adds the tools you need to get into the iMac, the mounting bracket, and the sensor to regulate fan speed. (2) It's easy to miss that OWC sells "Electra" and "Extreme Pro" SSDs; the latter are faster, have a longer warranty, and cost just a little more.
     
  19. maflynn Moderator

    maflynn

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    #19
    Agreed.

    Take a look at what ifixit has:
    iFixit Replace Drive
     
  20. hfg macrumors 68040

    hfg

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    Dec 1, 2006
    Location:
    Cedar Rapids, IA. USA
    #20
    BEFORE YOU DO THIS ...

    Be sure to fully back-up your Fusion drive to a bootable external disk.

    Breaking the Fusion drive into separate HDD and SSD components will destroy all your data contained on that drive. Once done, you will have to re-install the OS and your data to the SSD, and if it doesn't fit, the remainder will have to be put on the HDD.
     
  21. tentales macrumors 6502a

    tentales

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    Dec 6, 2010
    #21
    I think the OP understands that. Apparently you didn't fully read what he wrote.
    He DOES NOT want to use the HDD at all because of the noise it makes. He's well aware of needing to re-install the system (as he stated) and as a consequence break his current install.
     
  22. maflynn Moderator

    maflynn

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    #22
    Perhaps, but someone else wondering into the thread may not be aware, or at the very least to reinforce the idea that unfusing (or fusing) is a destructive process and you will lose your data. Having a backup on any work on your hard drive is a good idea :)
     
  23. tentales macrumors 6502a

    tentales

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    Dec 6, 2010
    #23
    Well then, ANY action on one's data storage should always be prefaced with "backup first".
    Guess after my 30 years in this industry, it's as ingrained as brushing your teeth before bedtime, hence I considered it somewhat superfluous. But yea, maybe the uninitiated. Reminds me of my first week tutorial in college, when the UNIX admin told us to type "rm -rf" on our home directories, to see what happens :)
     
  24. maflynn Moderator

    maflynn

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    #24
    Yes, that is solid and sound practice to embrace. :)
     
  25. gnasher729 macrumors P6

    gnasher729

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    Nov 25, 2005
    #25
    That's right, if you can hear the HDD, you either have extraordinary ears and are using your Mac in an absolutely quiet environment, or the drive is broken or near broken.
     

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