Should I save ram space on my SSD?

Discussion in 'OS X Mountain Lion (10.8)' started by aryattack, Jun 16, 2013.

  1. aryattack macrumors newbie

    Jan 1, 2009
    Because of financial reasons (student) I had to purchase a relatively small SSD (60 GB) and decided to do the optibay setup. I was hoping I could write some programs to my HDD but I have learned this is not possible. It seems as if my SSD is quite full despite having almost no additional applications, so does that mean the OS automatically allocates some space for my ram (16GB) for hibernations or should I just always leave that much saved? My SSD has only about 20GB left and I would like to install some Adobe apps.

    I do have trim enabler installed. Capacity is 59GB and I have 21GB left according to get info.

    Any help is appreciated, thanks!
  2. GGJstudios macrumors Westmere


    May 16, 2008
    It's always recommended that you keep 10-20% of any drive free, for your Mac to operate efficiently. It's not just space for paging, but also space for caches, logs, app work space,etc.

    Freeing up drive space in Mac OS X
  3. davidlv macrumors 65816

    Apr 5, 2009
    Kyoto, Japan
    Basically, you need to set hybernation mode to 0 and then delete the related file, which will save the same amount of space as your RAM, you have 16GB right? That's a big chunk of space with a small 60GB SSD! :eek: Save up some money and get a bigger disk when you can....:cool:
    Here are the terminal commands; (all found on this forum, can't give credit where it is due)
    Open a Terminal shell (in the /Applications/Utilities folder)
    pmset -g
    will list all the current power settings/device settings.
    1. set hibernate mode to 0
    sudo pmset -a hibernatemode 0
    hibernationmode 0 is normal sleep, data kept in ram, nothing written to disk
    2. delete the unnecessary sleep file (since hibernate is disabled) to regain disk space equal to memory (saves the same amount of disk space as your RAM, eg. 8 GBs, valuable on an SSD),
    You can use the Go to folder menu to delete the file, found in the /var/vm/ folder, and named sleepimage. Reboot and simply delete that file,. Or use this:
    sudo rm /var/vm/sleepimage or sudo rm /private/var/vm/sleepimage
    The sleep image file is actually in /Private/var/vm/ but /var/vm/ is a symbolic link to that location.
    Optional: Create a blanked zero-byte file so the OS cannot rewrite the file:
    sudo touch /private/var/vm/sleepimage
    Make the file immutable:
    sudo chflags uchg /private/var/vm/sleepimage
    3. If pmset -g shows: autopoweroff**1,
    disable this automatic hibernation mode (happens even if hibernation mode is set to 0 on the new Mac mini 2012 and iMac)
    sudo pmset -a autopoweroff 0
    4. set the safe sleep timer (standbydelay) to 20 hours, default is 4200
    sudo pmset -a standbydelay 72000
    5. sudo pmset -a standby 0
    While researching this, I noticed that bit 3 of hibernatemode encourages the dynamic pager to page out inactive pages prior to hibernation. So this appears to be why I have swap used after sleeping (even though my hibernatemode is 0, so bit 3 is off). I disabled this new, possibly buggy behavior by switching off standby: sudo pmset -a standby 0

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