Optimal use of SSDs on OS X systems

29 August 2011 • Posted by Ed_Saxman in OSX86 Tutorials • • 0 comments  


Since the advent of SSDs, and given its progressive lowering, are increasingly those who decide to replace its archaic system HD mechanic for one of these efficient storage systems.

To optimize its use and longer life it is advisable to try to avoid unnecessary writes to the SSD, and use it to read most of the time. With this guide we will try to avoid the progressive degradation inherent in this type of flash memory technology in a few simple steps. I hope it will be useful.

1- Disables the rest of the disc:

The use of this function does not make sense with SSDs, and sometimes gives problems with some brands.

System Preferences / Energy Saver, uncheck the box “Put the hard disk to sleep when possible”

If it's a laptop, turn it off both battery, as with plug.

2- Disable the Sudden Motion Sensor (portable):

This is a system designed to detect that the laptop is in free fall to the ground, and park the heads before landing HD. Again it is a pointless feature if you only have an SSD in the team.

Open the terminal, and write:

sudo pmset -a sms 0

3- Disable Sleep:

When we go into Sleep mode, and while the machine is plugged into the mains or battery available, RAM are still feeding, that is what keeps the team awake state. But we can avoid making flushed to disk, only used in case of mains fall, UPS or battery or laptop:

sudo pmset-a hibernatemode 0

sudo rm / var / vm / sleep Image

3B- Disables the button “Repose” Apple menu

If you do not use the Sleep and you want to avoid giving in error, you can leave the inactive button (in gray) with this command:

sudo defaults write /Library/Preferences/SystemConfiguration/com.apple.PowerManagement SystemPowerSettings -dict SleepDisabled -bool YES

And restart to apply changes. To reverse, just repeat the command would require changing the final: -bool NO

4- Disable if you do not use Spotlight:

Although the system comes with Spotlight, is a little cake and there alternatives to search the computer. You can disable it with:

sudo mdutil-to-i off

If you decide to switch applications, You can also selectively disable Spotlight indexing where to System Preferences / Spotlight, Flange “Privacy”, and adding the button + partitions on which we do not want Spotlight to act.

5- Enables support for SSD TRIM:

Note: This solution is better than using Trim Application Enabler. Unlike the latter, here does not replace any system file, only if tan parchea.

Note 2: Now you have this new alternative (2-September-2011): http://www.hispasonic.com/foros/trim-patcher-for-lion-snow/379773

If you have a SSD TRIM support, but we have not purchased from Apple, We will see that support castrated. To activate, only need to delete the ID check.

Run these 3 commands, pressing the Enter key after each:

sudo perl-pi-e ‘s|(\x52 x6F x74 x61 x74 x69 x6F x6E x61 x6C x00{1,20})[^\x00]{9}(\x00{1,20}\x51)|$1\x00\x00\x00\x00\x00\x00\x00\x00\x00$2|sg’ “$1″ /System/Library/Extensions/IOAHCIFamily.kext/Contents/PlugIns/IOAHCIBlockStorage.kext/Contents/MacOS/IOAHCIBlockStorage

sudo kextcache -system-prelinked-kernel

sudo kextcache -system-caches

6- Move user folders to HD (desserts):

If you have an SSD and HD, the best we can do for the first is to move user folders to HD. It is better to always leave an Admin account on the SSD, if at some point we have to boot without the HD.

Create a second user account, and logged with her. Go to the folder / users of your SSD, and copy the new user's folder to the new location. It's a good idea to create a partition on the HD exclusively dedicated to user accounts. This way all user files are separate from the operating system, which in itself is also a good measure of data protection.

Now from “System Preferences / Users and Groups”, right click over the new user, and agree to “Advanced”:

In section “Home Directory” will appear in principle / Users / UserName.

Click on “Select ..” and look for the user folder we copied over to HD, with what we will be a path like / Volumes / NombreDePartición / UserName, as shown in the screenshot above.

From the restart, user folder will be located in the HD, (have the house icon, when that user logueémos) so we can delete the original, located in / Users /

7- Active noatime:

Each time we access a file in OS X, amending its last access date. We can turn it off to avoid unnecessary writes on the SSD:

Copy this com.noatime.root.plist  to the path / Library / LaunchDaemons /

and restart (if you are using Lion)

After restarting, You can check that the command works with noatime “mount” in the terminal.


Note: For systems prior to Lion, additional steps at this point. If you've already finished Lion with point 7.

We will create the folder / bin / usr / local:

mkdir-p / usr / local / bin

cd / usr / local / bin

Copy to the route is Script.

Now open the terminal and type:

sudo chmod x /usr/local/bin/remount_noatime

sudo defaults write com.apple.loginwindow LoginHook /usr/local/bin/remount_noatime

salt of the terminal and reboot.


Ed_Saxman – AppleOSX86.com

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