iMac System Preferences: The Time Machine Pane
Mac users are justifiably proud about the Time Machine automatic backup feature that’s built in to Mavericks. Found in System Preferences, you can easily configure how Time Machine handles your backups from the pane shown in the following figure.
Of course, you’ll need an external hard drive (or an AirPort Time Capsule wireless backup station) for the best backup security. Note that Time Machine won’t work with an internal or external DVD drive: It’s got to be a hard drive.
However, if your Wi-Fi network uses an AirPort Extreme base station, you can connect an external hard drive to the base station’s USB port for use with Time Machine. Your iMac will back up wirelessly to the base station’s drive, just like Apple’s AirPort Time Capsule device!
To enable Time Machine, click the On switch and then click the Select Disk button to choose a disk to hold your Time Machine backup data. Time Machine backs up all the hard drives on your system. However, to save time and hard drive space, Time Machine allows you to exclude specific drives and folders from the backup process. Click the Options button, click the Add button (with the plus sign) to select the drives or folders you want to exclude, and they appear in the Exclude list.
To remove an excluded item, select it in the list and click the Delete button (with the minus sign). Note that the Estimated Size of Full Backup figure increases, and Time Machine adds the item you deleted from the list to the next backup.
By default, Mavericks warns you when deleting older backup files, but you can turn this warning off from the Options sheet as well.
If you enable the Show Time Machine in Menu Bar check box, you can elect to back up your Mac immediately by clicking the Time Machine icon in the Finder menu bar and then choosing Back Up Now.