Time machine is the default option for backup on every Mac running OS X since the introduction of Leopard (OS X 10.5) back in 2007. Although Time Machine wasn’t the first backup software from Apple. It’s probably safe to say it was the first serious application of its kind that the company has produced. As you’d expect, TIme Machine is integrated into the OS itself and is designed to be very straightforward to use. Connect a Mac-formated external drive to your Mac, and OS X will ask you if you want to set it up to be used with Time Machine. Using a drive with it doesn’t mean you can’t use that drive with anything else – you can still use the drive to store files using the Finder in the normal way.
Within just a few clicks, you can be backing up your files. Then, every time you connect that drive, Time Machine will, after a few seconds, start backing up anything that’s changed or new. Once you’ve done the setup, Time Machine is designed to need as little intervention from you as possible, and to be almost invisible until the point when you need to restore a file, at which point it will step in and save the day!
Time Machine doesn’t simply copy or “clone” everything that’s on your hard drive. Instead, once you’ve created one initial back up, it creates incremental backups and, using a clever piece of interface design, allows you to step “back in time” to find a deleted file.
It’s not an archive program, though: it’s designed to capture the most recent state of data on your disk, as well as file you’ve deleted, rather than archiving multiple versions of the same file in a reliable way. If the latter is what you want, then you need to use the auto-save and versioning feature introduced with OS X 10.7 Lion.
By default, Time Machine will save backups hourly. However, as you’d imagine, if it saved an hourly snapshot of every file, your backup drive would fill up very quickly. So instead, it saves the hourly backups for the past 24 hours, then consolidated daily backups for the last month and a weekly backup for everything older, until your drive runs out of space. At that point, it will delete the oldest weekly backup.
How bi a drive you need to use will, of course, depend on how big your hard drive is and how many old backups you want to store. Something double the size of your internal drive will allow you plenty of rooms for backups., but you can use Time Machine with something the same size too, if you don’t want to store many old files.
If you have a smaller drive you want to use, you can set Time Machine to exclude files or folder on your drive. For example, you might decide that since you can always reinstall your apps you can live without having a backup of your Applications folder. Once you opt to exclude it in Time Machine’s preferences, anything in that folder will no longer be backed up.
Remember, thought, that what Time machine won’t do is create a bootable version of your hard drive, which means that in the event of having a complete hard-drive failure you’ll need to wipe it, reinstall OS X from a recovery disc and then restore your files from your Time Machine backup.
Time Machine backup don’t have to be made to a drive disconnected directly to your Mac. Instead, you can use any network-attached storage drive formatted as “Journaled HFS+” that you’re connected to over a network, including (naturally) Apple’s own dedicated Time Capsule device – see www.apple.com/timecapsule. You can also use USB drives attached to Airport Express Base Station, although this isn’t supported by Apple. Unfortunately, Time Machine doesn’t enable you to back up over the internet, only your local network.
Recovering a backup from Time Machine is simple. Select Enter Time Machine (either from the Dock or the icon in your menu bar) and Time Machine appears to float the active Finder window above an astronomical background. behind the current window is a “stack” of older versions, and you simply scroll back through this stack to find whatever deleted file you wish to retrieve.
In addition, some OS X application can work directly with Time Machine to recover information. For example, if you select Enter Time Machine while using Apple Mail, you can step back through deleted emails, in the same way as you can with items in the Finder. Other apps that support this include Contacts, iPhoto (’08 and newer) and GarageBand (’08 and newer).
If you’re restoring a whole drive, you’ll be likely to be using an installation or recovery disc. When you’re reinstalling OS X on a hard drive, the process gives you the option to restore the whole drive using Time Machine. Select this option, connect the drive with your Time Machine backup on it (or select a Time Capsule Volume) and let the software do the rest.
How To Restore From Time Machine
Time machine offers several options for restoring files. Restoring a specific file or folder begins in the Finder. First, go to where the file or folder was on your drive. Next, open Time Machine, and after a few seconds your Finder window will change to reveal what looks like a series of windows stretching back into space, with a bar on the right -hand side of the screen with dates on it. Scroll back through these tacked windows, moving “back” the older versions, until you find the file you’re looking for.
If your drive has been completely corrupted, boot your Mac from an OS X application disk (version 10.5 or later). Once it’s started up, select utilities from the menu bar, then Restore System From Backup… Plug in the drive your old disk was backed up to, and select it. Now, you’ll be able to restore your drive, including files and applications. However, Time Machine doesn’t back up applications cache folders, so when you first run some apps (such us Entourage) it may take a while to recreate its cache files.