Do SSD's and HDD's call for identical care?

Discussion in 'MacBook Pro' started by BudVitoff, Jan 8, 2017.

  1. BudVitoff macrumors newbie


    Aug 26, 2011
    Minneapolis, MN
    Actually, I know of one exception to that title. I just worded it that way to catch your attention.

    I know that defragging is not recommended for an SSD, for two reasons: 1) it’s not necessary, because, unlike HDD’s, there is no cost of latency time to switch to the next segment of a fragmented file, and 2) reshuffling multiple segments to glue them back together as a single segment represents a significant amount of "wear and tear" on the SSD — or words to that effect. Reason #2 gives me some concern about the life expectancy of an SSD, and I hope to see some replies to that concern.

    This post was born out of a recent Onyx run against our MBP, which found errors and suggested a repair run. I hesitated because somehow I had difficulty visualizing a "repair" of an SSD. So except for no defragging, can I feel comfortable treating an SSD exactly as I would an HDD, or are there other exceptions that I should be aware of?
  2. curmudgeonette macrumors 6502

    Jan 28, 2016
    Don't stick an SSD on a shelf for ten years. All the data needs to be rewritten occasionally. The normal wear leveling algorithm will take care of this - the drive simply needs to be used.
  3. steve23094 macrumors 68020


    Apr 23, 2013
  4. alex0002, Jan 8, 2017
    Last edited: Jan 8, 2017

    alex0002 macrumors 6502

    Jun 19, 2013
    New Zealand
    Perhaps a better way to look at it might be to ask, do you think that recent macOS releases been designed with SSDs in mind and are additional optimisations a waste of time?

    Do you have a recent apple provided SSD or a third party SSD?
    If third party, then additional advice might require additional information.

    If you have a recent apple provided SSD with a recent release of macOS, I don't think there is any real need for special care. Make regular backups in case the worst happens, just like you would with an HDD.

    If you have a third party SSD installed, you might benefit from using Trimforce.

    Regarding Onyx - perhaps this might help.

    I'm under the impression that Onyx is just repairing file system permissions and not messing around at the block level. If you have a recent version of OS X / macOS this might help too.
  5. BudVitoff thread starter macrumors newbie


    Aug 26, 2011
    Minneapolis, MN
    --- Post Merged, Jan 10, 2017 ---
    My original post was two-fold:
    1)The Onyx run was on my ex's MBP.
    2)My 2009 iMac is getting senile, and I'm planning to replace it with a new one. My history with the current one shows that 500GB is more than enough for my needs.
  6. Samuelsan2001 macrumors 604

    Oct 24, 2013
    Repair disk works just as well on ssd's as hard drives in disk utility, no idea on onyx but I can't imagine it doesn't work they are up to date with all the latest software.?

    Well you may just want to replace the HDD with an SSD in that old iMac that senility may well be a dying hard drive 5-6 years is about the time they start to die.
  7. Antairez macrumors regular


    Mar 17, 2015
    I would like to shorten your reasoning of defragmentation on SSD to

    1. Its useless.
    2. Meaningless wear.

    And to answer your question, it depends on what errors you are talking about. If you are talking about permission errors, Apple already provided Disk Utility for you to fix those things, so yeah feel free to run it as it keeps your system integrity in tact.
  8. maflynn Moderator


    Staff Member

    May 3, 2009
    I would add more specifically that defragmenting a SSD will shorten its life span, as you're incurring write cycles for no reason.
  9. cube macrumors G5

    May 10, 2004
    You might need to refresh the cells in the SSD once in a while.
  10. leman macrumors G3

    Oct 14, 2008
    The "repair" most likely refers to filesystem repair and has nothing to do with the SSD per se. As to your general question, my answer would be: just don't do anything. Uninstall all tools like Onyx and friends and use your computer normally. "Special care" is only needed when you actually have a problem.

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