Is TRIM work with Apricorn Velocity Duo x2

Discussion in 'Mac Pro' started by accessvirus, Aug 14, 2016.

  1. accessvirus, Aug 14, 2016
    Last edited: Aug 15, 2016

    accessvirus macrumors newbie

    Joined:
    Mar 1, 2015
    #1
    Problem solved.
    I contact the apricorn technical service:
    Sofware and hardware raid performances is similar. But if you want to use trim function you have to use apple sofware raid. No need change bios settings ;)

    I use 2pcs 480gb same ssd.

    Install Apricorn velocity duo x2 to PC for change bios setting. I choose raid0.

    After install it to mac pro 5.1. el capitan 10.11.6.( trim enabled)

    But system shows rotational 960GB HDD not ssd.

    Why I see rotational?

    In this case is trim work for rotational 960gb hdd? or not?

    I contact the apricorn technical service:
    Sofware and hardware raid performances is similar. But ıf you want to use trim function you have to apple sofware raid.
     
  2. AidenShaw macrumors P6

    AidenShaw

    Joined:
    Feb 8, 2003
    Location:
    The Peninsula
    #2
    I don't know the right answer for your question for that particular card - but by and large most RAID setups do not pass TRIM through to the drives.

    If it does pass through, the virtual disk created by the RAID software will show the "TRIM" attribute as supported by the virtual disk.

    If TRIM isn't supported, you can come pretty close by over-provisioning the disks to leave 10% to 20% unused space for the garbage collector.

    In your case, your 480 GB disk is probably a 512 GiB disk with a lot of over-provisioning already built in. If you do a "secure erase" or other hardware/firmware reset, you'll "TRIM" the entire drive.

    Then, create the RAID volume partition as 900 GB (instead of 960 GB). This will make about 17% of the volume unusable from the OS viewpoint - but it will give that 17% to the garbage collector for optimizing performance. With 17% over-provisioning it would be very hard to measure the performance improvement from true TRIM support.
     
  3. jbarley macrumors 68030

    jbarley

    Joined:
    Jul 1, 2006
    Location:
    Vancouver Island
    #3
    I boot from two 250GB SamSung evos setup as raid0 using Apple raid and they both show as Trim enabled.
     
  4. AidenShaw macrumors P6

    AidenShaw

    Joined:
    Feb 8, 2003
    Location:
    The Peninsula
    #4
    Does the virtual disk show up as TRIM enabled?
     
  5. jbarley macrumors 68030

    jbarley

    Joined:
    Jul 1, 2006
    Location:
    Vancouver Island
    #5
    I'm not sure that I'd care as long as the physical SSDs show Trim enabled.
    Having said that, "/sbin/fsck -fy" run from the command line in single user mode shows my startup volume (virtual disk) as having unused blocks trimmed.
    Good enough for me.:)
     
  6. knowhate, Aug 14, 2016
    Last edited: Oct 21, 2017
  7. accessvirus, Aug 15, 2016
    Last edited: Aug 15, 2016

    accessvirus thread starter macrumors newbie

    Joined:
    Mar 1, 2015
  8. AidenShaw macrumors P6

    AidenShaw

    Joined:
    Feb 8, 2003
    Location:
    The Peninsula
    #8
    Yes, it looks good for the virtual disk.

    The TRIM state for the physical drives isn't conclusive - if the virtual disk driver doesn't pass the TRIM commands through, then TRIM won't be used.

    Since fsck sees it, that's proof.
     

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