MBP 2010, EVO 850, TRIM, Ubuntu 12.04.5 on VMWARE 7

Discussion in 'MacBook Pro' started by fredfrog, Oct 1, 2016.

  1. fredfrog macrumors newbie

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    #1
    Its a complex setup and question.

    Macbook Pro 2010 running Sierra. Have Samsung Evo 1Tb with clone of system installed and ready to put in the machine but I'm not installing it physically until I sorted this question out. I read many things which present a confused picture about the use of TRIM, particularly concerning Linux.

    On this same system I also run VMWare 7.01 under which I run Ubuntu 12.04.5. This is essential to me as I use it to run a local clone of my Drupal server which I rsync with my server out there in remote virtual linux machine land. I don't want to update or port this setup because I only use it now to do drupal security updates and keep my content out there (I appreciate its way out of date in Ubuntu and VMware terms). From time to time I run other Linuxes under this VMware

    So - to enable TRIM or not.

    Here is one post that makes the picture very muddy.

    https://www.reddit.com/r/mac/comments/3bsne4/psa_be_careful_what_you_trim_in_10104/

    I'd like to enable TRIM but I'm unsure a) how the relationship between Ubuntu and disk systems works, particularly in 7.0.1 and b) how that relates to TRIM being different in Linux. I can cope with technical explanations, having worked with linux systems since before the 1.0 kernel and been in ICT for 35 years. My understanding is that TRIM relates to fragmentation/garbage-collection in file/disk systems but the precise details of that in SSD's I don't know. The thought of slow unrevealed data corruption horrifies me.

    andy
     
  2. keysofanxiety macrumors G3

    keysofanxiety

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    #2
    Modern SSDs have built-in garbage collection/sorting anyway, so it's not the end of the world if you don't enable TRIM.

    If you were using Linux as your main OS, I'd have said to avoid it. However because you're running it virtually, I can't see how TRIM enabled in OS X would affect the VM.

    A lot of VMs just use a disk driver anyway. For example, the 840 EVO in my 2012 MBP has the Samsung Magician software running in BootCamp. However when I access the same BootCamp partition through Parallels Desktop, it says it can't find a Samsung drive, as everything is virtualised. Similarly it doesn't detect the dGPU in devmgmt as being what it is; it's all virtual. I'm sure it's a similar thing on VMware.

    TL;DR: as long as Linux is ran virtually, I don't see a cause for concern with enabling TRIM in OS X. :)
     
  3. maflynn Moderator

    maflynn

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    #3
    Its not Ubunutu and the disk system, but rather Vmware and the disk system. Ubuntu does not see the physical disk system but rather a virtualized version, vmware handles all disk I/O interactions with the OS X.

    I'd say you're better off with TRIM enabled, especially if you are dealing with lots of deletes, as the the SSD will slow down w/o TRIM
     
  4. fredfrog thread starter macrumors newbie

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    #4
    Thank you keysofanxiety and maflynn. I think I concur. I *have* enabled TRIM. However, I'm going also (ouch) to update my VMware before I use that subsystem as the one I'm using goes back beyond SDD's. It *should* work but I can't ask VMware until I updated (they are miserable about support contracts). The SDD is fairly flying :).

    andy
     
  5. fredfrog thread starter macrumors newbie

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    #6
  6. bent christian Suspended

    bent christian

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    #7
    Samsung SSDs need TRIM for normal performance. Period.

    Garage collection is not adequate on these drives.

    I boot externally off of an 850 Pro via USB 3.0 (obviously no TRIM) that has gone from 400MB/s write, down to an erratic 90-200MB/s write speed. Read speeds have been a consistent 430MB/s. I only use this drive to hold the OS, applications, and libraries, etc, so it is still fast for my uses. Not much writing happening. I have discussed this with Samsung and have tried every remedy imaginable, to no improved result.
     
  7. JTToft macrumors 68040

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    #8
    - You could connect it once in a while to a native SATA interface to manually TRIM it. Or move to permanently connecting via Thunderbolt rather than USB.
     
  8. bent christian Suspended

    bent christian

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    #9
    Neither of these are an option. For my uses the drive is fine, as almost everything being written goes to the interal Fusion (documents, scratch disks, caches, etc.). I am guessing the OP wants do more with his/her SSD. If you are writing to these drives, they absolutely need TRIM enabled.
     
  9. JTToft macrumors 68040

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    #10
    - I've read about at least one SATA-USB chipset that allows the passing of ATA commands such as TRIM. Perhaps worth looking into.
     
  10. fredfrog thread starter macrumors newbie

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    #11
    Thanks guys. As the OP I hope my worry is solved. I *am* using TRIM and have been running my linux systems as a VM - they seem fine but it may be some time before data corruption becomes an issue. I have only three external clone backup disks which I rotate on a queue so any data corruption will be quickly propogated and by the time I know about it it will be too late. I am, for the time being, keeping an additional backup of the critical linux on another disk (not big enough for max clone) in case of issues discovered later. The main problem is probably my own confidence in it - if its critical and I know its not bomb-proof in backups then I worry. Undetected data corruption is evil if one can't afford to keep backups back to the dinosaurs.

    Thanks to all

    andy
     
  11. fredfrog thread starter macrumors newbie

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    #12
    And just to cap it off for those on older Macbooks - backup to an external moving platter drive is at least twice as fast (and I thought the bottleneck was the Firewire 800 pipe). It wasn't, clearly it was the drive. Not yet backed up to what was the internal drive before the swap - it will be interesting to see how fast that goes - if it goes faster I will be pretty baffled.

    andy
     
  12. bent christian, Oct 4, 2016
    Last edited: Oct 4, 2016

    bent christian Suspended

    bent christian

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    #13
    I have a couple of 3.0 enclosures that I have tried and I use one of these for migration USB 3.0 to SATA III).

    [​IMG]

    None have given TRIM support. I haven't seen anyone write that they have had success in getting the commands passed on through UBS 3.0 or 3.1. I do not think it is possible. If it were, everyone would using that chipset and no one would be using those cheap Thunderbolt enclosures. There only reason why StoreJet and the like exist is to provide relatively inexpensive assess to TRIM. USB 3 is faster in most cases, until it the drive gets bogged down.
     
  13. JTToft macrumors 68040

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    #14
    - Some quick Googling haven't yet led me to what I read a few months ago on it. But I'll see if I can dig it up.
     
  14. bent christian Suspended

    bent christian

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    #15
    I have done quite a bit of investigation over the past several months. There isn't a USB adapter that supports TRIM. If there was, everyone would be using it and it would be easily found.
     
  15. JTToft macrumors 68040

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    #16
    - I was leaning toward that conclusion as well, and still am to a certain extent. It's a shame I didn't save it and can't remember in detail what it was. It might not even have been a product in existence but only a theoretical possibility.
    I need to do some digging. Hang tight.
     
  16. Weaselboy Moderator

    Weaselboy

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    #17
    You are correct. USB cannot pass along the SATA TRIM command.

    What some people have read and it has caused confusion, is some UASP (USB-attached SCSI protocol) enclosure chipsets can convert the SCSI Unmap command (similar to TRIM) to TRIM commands at the drive. Windows can run this SCSI Unmap command with the Powershell command Optimize-Volume and the -ReTrim option. OS X cannot run the SCSI Unmap command (at least not that I have been able to find). So at this point, no matter what chipset you use, you are not going to get TRIM over USB on a Mac.

    There is some discussion at the bottom of this article.
     
  17. JTToft macrumors 68040

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    #18
    - So what I'm reading is that TRIM is possible in a roundabout way, but that OS X can't do it currently in that roundabout way. Correct?
    In your linked article, Anandtech claims that both reviewed enclosures have "no trouble supporting TRIM" (in that roundabout way).

    I also found these bits on the SanDisk Extreme 500 external SSD and the Corsair Flash Voyager GTX flash drive:

    http://www.anandtech.com/show/9847/sandisk-extreme-500-portable-ssd-review

    http://www.anandtech.com/show/8567/corsair-flash-voyager-gtx-usb-30-256gb-flash-drive-capsule-review
     
  18. Weaselboy Moderator

    Weaselboy

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    #19
    Correct. The UASP controller converts the SCSI Unmap command to TRIM and Windows can do that (pass the Unmap command). I think that is what is happening in those two tests you linked, although they don't go into the under the hood workings like the article from Anandtech I mentioned.
     
  19. JTToft macrumors 68040

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    #20
    - I'd guess so, too. So it is actually possible, which is pretty cool. Just not on the majority of SATA-USB chipsets and not yet in OS X.

    Considering Apple's disregard for cool protocol standards (seriously, when are we going to get DisplayPort daisy-chaining?), it's probably a long way off, too.
     
  20. bent christian Suspended

    bent christian

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    #21
    I doubt it will ever happen. Apple wants everyone to buy internal SSDs at their own inflated prices.
     

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