TRIM + Encryption?

Discussion in 'MacBook Pro' started by hehe299792458, Jul 9, 2011.

  1. hehe299792458 macrumors 6502a

    hehe299792458

    Joined:
    Dec 13, 2008
    #1
    I have a SF-2281 based SSD, and according other members here, it seems better to leave TRIM disabled and leave it to Garbage Collection.

    However, I am planning to encrypt my entire disk with PGP. Does that factor into whether I should TRIM my drive or not? I know encrypting the drive would mean writing over every single cell, so how would that impact performance without TRIM? And with TRIM?
     
  2. maflynn Moderator

    maflynn

    Staff Member

    Joined:
    May 3, 2009
    Location:
    Boston
    #2
    Encryption and TRIM are two different technologies working on different levels.

    TRIM basically means that when a block of data is deleted, the drive is notified instead of just marking its reference deleted, the data is actually deleted. It does not matter if that data block is encrypted or not.
     
  3. hehe299792458 thread starter macrumors 6502a

    hehe299792458

    Joined:
    Dec 13, 2008
    #3
    But I believe PGP writes over the entire disk with its encryption. In effect, won't that be tantamount to erasing free space in disk utility? And if so, wouldn't erasing free space without TRIM enabled bring significant speed decreases?
     
  4. maflynn Moderator

    maflynn

    Staff Member

    Joined:
    May 3, 2009
    Location:
    Boston
    #4
    Oh I see what you're saying - my mistake.

    Yeah the PGP disk image becomes a "drive" internally and thus TRIM cannot perform its actions.

    Why not wait for Lion to come out and use its whole disk encryption. I don't know the details of that and how TRIM will work but I do see your point regarding PGP

    Sorry for the misintereptation.
     
  5. hehe299792458 thread starter macrumors 6502a

    hehe299792458

    Joined:
    Dec 13, 2008
    #5
    Lion's FileVault will probably be great, but I've used PGP for so long that I'd rather stick to it if possible.
     

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