Optimizing Snow Leopard for SSD drives….

I just installed a new 128GB SSD drive in my older C2D 17″ macbook Pro and let me tell you….WOW….This thing is on fire. The system is extremely responsive and apps literally jump onto the screen. The machine now boots up to full desktop in roughly 17 seconds. Now that’s nice. I did do a bunch of changes to the way Snow Leopard is setup to optimize a couple of things that are normally tuned for HDD’s.

  • Turn off Sudden Motion Sensor (SMS): If you are replacing your primary (and only) HDD internal drive with a SSD, you can get a bit of a performance boost by turning off the Sudden Motion Sensor technology that comes with your laptop. Remember your SSD doesn’t use read/write head on rigid platters so there is no reason to keep this feature turned on. You can safely turn it off by issuing the command below in Terminal, type in administrator password when asked.
    sudo pmset -a sms 0
  • Turn off hibernation and delete sleepimage file: Using SSD, you can achieve under 20 seconds boot-up time. Why bother using Hibernation and waste too much space on your SSD. To do so, issue the commands below in Terminal, enter administrator password when asked.
    sudo pmset -a hibernatemode 0
    sudo rm /var/vm/sleepimage
  • Reduce disk I/O by mouting partition with noatime: Stop OSX from updating “last access time” or atime everytime a file is touched on your filesystem. This is IO expensive and unnecessary. In a terminal window create a file called com.nullvision.noatime.plist under /Library/LaunchDaemons folder and stick the following lines in the file. Save the file (you need to sudo when you edit the file) and reboot your machine.
    <?xml version="1.0" encoding="UTF-8"?>
    <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN"
            "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
    <plist version="1.0">
        <dict>
            <key>Label</key>
            <string>com.nullvision.noatime</string>
            <key>ProgramArguments</key>
            <array>            
    		<string>mount</string>
                	<string>-vuwo</string>
                	<string>noatime</string>
                	<string>/</string>
            </array>
            <key>RunAtLoad</key>
            <true/>
        </dict>
    </plist>

    Once the machine has rebooted you can check to make sure your root partition is mounted with noatime by issuing the following command

    mount | grep "/"

    and look for something similar to this in the output

    /dev/disk0s3 on / (hfs, local, journaled, noatime)

This should do it. Have fun with your new SSD drive.