How to enable S.M.A.R.T on SSD

Discussion in 'Mac Accessories' started by EthanBZ, Mar 26, 2014.

  1. EthanBZ macrumors newbie

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    #1
    Hi
    I have 2 ssd's one is a oyen digital thunderbolt external ssd and the other a samsung 840 evo with a 2.0 usb to sata connection.

    I would like to know if there is a way to enable SMART. ?

    The oyen digital has SMART enabled but the samsung does not, even though it has the capability.

    One other thing that i have noticed is that when not in use but just plugged in the oyen digital gets hot where as samsung does not is there a specific reason for this ?


    any help would be appreciated.
     
  2. ColdCase, Mar 26, 2014
    Last edited: Mar 26, 2014

    ColdCase macrumors 68030

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    #2
    Most USB controllers/enclosures do not support smart data. SMART is defined for SATA and SAS type interfaces. Dunno off hand if the OS supports grabbing smart data off a USB device, even if the controller supports it.

    There may be a utility, I'm sure someone more helpful will chime in here soon.

    Does the oyen have an indicator light that is warming things up?
     
  3. Fishrrman macrumors G3

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    Feb 20, 2009
    #3
    Both the "Smart Utility" and "SmartReporter" utility apps see and report on my SSD mounted in an external USB3/SATA docking station.

    The dock is a plugable.com "lay-flat" USB3/SATA dock, with an ASMedia 1053e controller chip that supports UASP (USB Attached SCSI Protocol).

    I'm going to -guess- that the UASP support has something to do with this (that's -only- a guess).
     
  4. EthanBZ thread starter macrumors newbie

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    #4
    The oyen has a blue internal light but the housing feels very warm over most of its surface.

    I have downloaded the smart softwares from the app store and will see how they work.

    As you have said i will see if UASP helps with ssd capabilities as i have ordered a USB 3.0 to sata iii with UASP


    What puzzles me is that one has SMART enabled and the other does not even when both are solid state drives, the only difference is the connector and brand.
     
  5. ColdCase macrumors 68030

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    #5
    Thunderbolt is SATA native (OS talks to drive via SATA commands) where USB is not (SATA commands gets transcoded to USB). The USB controller has to do extra work to support SATA features like SMART, and most do not seem to.
     
  6. EthanBZ thread starter macrumors newbie

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    #6
    will a USB 3.0 with supported UASP be any better at transcoding ?
     
  7. ColdCase, Mar 27, 2014
    Last edited: Mar 27, 2014

    ColdCase macrumors 68030

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    #7
    Its not so much transcoding but support for SATA command sets (i.e. sata command pass through). I have a SSD with a USAP enclosure. SMART is not supported through a USB 3.0 hub. I need to wait another two hours for the machine to free up so I can check direct connection. Someone else may pop in here by then.

    ----------

    Active SMART 2.6 for USB drives supports following USB hard drive models:
    - Western Digital Passport hard drives;
    - I-O Data hard drives;
    - Trekstor USB boxes;

    So there are some USB enclosures that support SMART.

    Also see:
    http://sourceforge.net/apps/trac/smartmontools/wiki/USB
    and:
    http://sourceforge.net/apps/trac/smartmontools/wiki/Supported_USB-Devices
     
  8. ColdCase, Mar 27, 2014
    Last edited: Mar 30, 2014

    ColdCase macrumors 68030

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    #8
    The recent StarTech USB enclosure I have supports UASP but does not appear to support SMART. I think its a chip by chip, vendor by vendor thing. The enclosure appears to use ASMedia Technology.
     
  9. EthanBZ thread starter macrumors newbie

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    #9
    I have tried both ssd's in the oyen digital enclosure and the startek USB 3.0 with UASP supported.

    S.M.A.R.T is supported on both of them now but i can't see if TRIM is enabled for the USB connected device.

    The reason i ask is that i want to see if it makes a difference in MBps as the read/write is lower than the ssd/USB should be capable of. I'm getting W387 R400 on black magic or W285 R365 on AJA system test

    Surprisingly the TB is almost the same in terms of performance except it has a faster read speed.
     
  10. SaSaSushi macrumors 68040

    SaSaSushi

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    #10
    USB-attached SSD Drives cannot use TRIM. TRIM commands are only for SATA attached drives. Thunderbolt-attached drives are properly recognized as SATA and thus are able to use TRIM.
     
  11. ColdCase macrumors 68030

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    #11
    Doesn't some USB controller pass through some or all the SATA commands? They have to pass through commands to support SMART.
     
  12. SaSaSushi, Mar 30, 2014
    Last edited: Mar 30, 2014

    SaSaSushi macrumors 68040

    SaSaSushi

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    #12
    Yes, SMART data can be accessed from drives in SAT compatible USB enclosures in OS X by use of the OSX SAT Smart Driver.

    However, and someone more knowledgeable than I can correct me if necessary, I believe that the OS will only issue TRIM commands directly to connected SATA devices and not to devices on the USB-SATA bridge.

    If you look at the information in System Profiler for attached USB storage devices, while you will see SMART status, there is no TRIM status.

    As mentioned, Thunderbolt-attached HDDs and SSDs use Thunderbolt AHCI and are recognized as directly connected SATA drives.
     

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