TRIM vs Garbage Collection in RAID 0

Discussion in 'Mac Pro' started by ZombiePhysicist, Jul 12, 2014.

  1. ZombiePhysicist macrumors 6502

    ZombiePhysicist

    Joined:
    May 22, 2014
    #1
    Hi all:

    Does TRIM work when you've RAID 0'd your drives, like in a sonnet tempo? Because if not, then it may make sense to get drives, like one of the OWC drives, that does garbage collection in the background despite the drives being in RAID.
     
  2. Killerbob macrumors 6502a

    Joined:
    Jan 25, 2008
    #2
    I don't have an answer for you, but I look forward to hearing one...

    I have an Accelsior Card in a Sonnet Echo box, along with the Sonnet Tempo Pro (w. 2x Samsung 840 Pro SSDs), and wonder if I should use TRIM. I also have a Samsung rugged disc.

    When I check Trim Enabler, it says "The patch is not active, but Trim is working. You probably have an Apple SSD, which supports Trim by default."

    However, in System Information I get the following:

    Apple SSD SM1024F - TRIM Support: Yes
    Samsung SSD 840 EVO 500GB (ext. TB disc) - TRIM Support: No
    OWC Mercury Accelsior PCIe SSD - No TRIM mentioned
    2 x Samsung SSD 840 PRO Series - TRIM Support: No

    I wonder what would happen if I turned on the TRIM patch?
     
  3. ZombiePhysicist thread starter macrumors 6502

    ZombiePhysicist

    Joined:
    May 22, 2014
    #3
    Thanks Killerbob. I believe the accelsior does it's own garbage collection, so you don't need TRIM on it. Curious about your tempo pro and if it needs TRIM or not. Not sure if the 840's have garbage collection in the absence of TRIM.

    Have you had the 840/sonnet setup for a long while? Is the write performance on it still about as fast as new? If so, then it's doing some garbage collection and it also doesn't need TRIM.
     
  4. hfg macrumors 68040

    hfg

    Joined:
    Dec 1, 2006
    Location:
    Cedar Rapids, IA. USA
    #4
    Trim seems to be working fine on my RAID-0 Sonnet Tempo Pro OSX boot drive. This is with a pair of Crucial 512GB M4 drives using the popular "Trim Enabler" by Cindori.
     
  5. Killerbob macrumors 6502a

    Joined:
    Jan 25, 2008
    #5
    I am never one to let down a challenge, so I turned on Trim Enabler by Cindori:)

    It works fine on the Sonnet Tempo Pro, and the Samsung 840 Pros as well. It does not work on the Accelsior Card though, so it must utilise its own garbage collection. I have the Accelsior card in a Sonnet Echo Box, connected via TB2 to my nMP, and it is fast. The Tempo Pro card with 2 Samsung 840s is faster though...

    I "only" use the Tempo for scratch in Adobe applications, and the Accelsior is used for BU, and I haven't notised any degradation in speed.
     
  6. ZombiePhysicist thread starter macrumors 6502

    ZombiePhysicist

    Joined:
    May 22, 2014
    #6
    Thanks HFG and Killerbob. Did you ever try the sonnets in raid without enabling TRIM? Meaning, did the 840evo's garbage collection keep it running fast without TRIM?

    Have you tried some speed tests over time and notice that the write speed stays quick so you feel confident that either the garbage collection or TRIM was working?

    In general, I prefer using garbage collection and avoiding TRIM, but other than the OWC drives, I'm never sure if other manufacturers really offer garbage collection. And I'm thinking of getting the sonnet and going to a 2TB RAID0 (since OWC hasn't updated the capacity of the accellsior or other drives in quite a while).
     
  7. ZombiePhysicist thread starter macrumors 6502

    ZombiePhysicist

    Joined:
    May 22, 2014
    #8
    Thanks Lou. It's not totally clear to me that the samsung has garbage collection. i see it as a stat on some of their spec sheets, so I'm assuming it's there. But I haven't seen a confirmation that it is there. Meaning, it works even when TRIM is off, the drive writes stay fast.

    My guess is that all modern SSDs *should* have this, and it makes things moot.

    What still isn't clear to me is the interaction of RAID 0 (in both software and hardware variants) and TRIM. I would suspect if you use OS X RAID 0 software to join two drives, TRIM should still work as it maps everything. But if RAID 0 is run by the controller card, not sure if the OS really knows what areas to map out.
     
  8. hfg macrumors 68040

    hfg

    Joined:
    Dec 1, 2006
    Location:
    Cedar Rapids, IA. USA
    #9
    My take on both those articles was similar.

    Although modern SSDs have GC as part of their design, being able to synchronize that with OS operations using Trim makes it much more efficient.

    I got the feeling that the RAID discussion (from 2012) was focused on "hardware" RAID implementations due to their popularity for maximum performance. The "software" RAID we are using with the Sonnet cards wasn't directly addressed, and I think might fall into the same category as standard OS trim applied to each individual SSD in the array.


    Thanks for the links Lou...
     
  9. flowrider macrumors 601

    flowrider

    Joined:
    Nov 23, 2012
    #10
    I agree, and IMHO, OWCs stand that their drives do not need TRIM is pure folly on their part.

    Lou
     
  10. TheHerdForever macrumors member

    TheHerdForever

    Joined:
    May 11, 2012
    #12
    Bump!!
     

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