Crashplan on Windows has a taskbar icon that lets you put the backup daemon to sleep, but the Mac OS X port doesn’t seem to have this functionality.

You can’t just kill the backup daemon process. The OS X “launchd” superviser daemon will see the process go away, and immediately respawn the process. You have to tell launchd to stop the backup daemon by using the launchctl command:

sudo launchctl unload /Library/LaunchDaemons/com.crashplan.engine.plist

The crashplan daemon will start again after you reboot, or you manually restart it:

sudo launchctl load /Library/LaunchDaemons/com.crashplan.engine.plist