You might use your Mac to keep your music and photo collections organised, upload a blog to your web space, or keep in touch with friends and family through email. However you use yours, most of us have some of our most cherished memories stored on our hard drives.
All of which means it's essential to keep those precious files backed up, just in case a hard disk failure strikes your system. Until the release of Mac OS X 10.5 (Leopard), backing up was left to the individual Mac user. With Leopard, however, Apple introduced Time Machine, which you might call 'backup for the rest of us'.
The first time you plug an external FireWire or USB 2.0 hard disk into your Mac you'll be asked if you want to use it as your Time Machine backup disk. If you do, click Use as backup disk, and Time Machine will automatically take over.
However, it's a good idea to find out more about how Time Machine ticks so that you can fine-tune it to your exact requirements. You might, for instance, want to change the interval between backups, or perhaps exclude certain folders from being backed up in the first place.
The first thing you should know about Time Machine is that the external hard disk you use needs to be formatted in a specific way in order to work properly; if you don't do this, backups might stop when the amount of data backed up reaches around the 10GB mark. Many manufacturers – LaCie and Western Digital, for instance – make a selection of products specifically targeted at Mac users that offer plug-and-play capability, while other products might be more suited to use with Windows, unless you reformat them first.
If you're at all unsure when buying a disk for use with Time Machine, check the specification. Once you have the disk you can use Mac OS X's Disk Utility to confirm that the disk will work properly and make changes to the formatting if needed. Here's how:
1) With the disk plugged into your Mac, launch Disk Utility (from Applications > Utilities).
2) On the left of the Disk Utility window you'll see a column that contains icons for all the disks attached to your Mac, either internally (your Mac's startup disk, for instance) or externally. Each disk has a
physical description – for instance, '111.8GB Fujitsu' – below which (and slightly inset) will be one or more icons describing the volumes into which the disk is subdivided. Click the main physical description of your intended backup disk, and look at the status information in the bottom right-hand corner of the Disk Utility window. If you're going to use the disk with a PowerPC Mac, the Partition Map Scheme should read Apple Partition Map; if you're using it with an Intel Mac it should say GUID Partition Table. If it reads Master Boot Record, the disk has been formatted for use with a Windows PC, and must be reformatted.
3) Next, turn your attention to the formatted volume listed below the main description of your external hard disk. Click its name and check the description of its format in the bottom-left corner of the Disk Utility window. This should read Mac OS Extended. If it reads MS-DOS (FAT32), the disk must be reformatted.
A guide to preparing and using disks with Time Machine follows.
Time Machine and AirPort Disks
If you're lucky enough to have an AirPort Extreme Base Station and Mac OS X 10.4.8 or later, you can connect a USB 2.0 hard disk to the Base Station for use as an AirPort Disk for sharing files across the wireless network. Unfortunately, if you have Leopard, you can't (at the time of writing, anyway) use your AirPort Disk with Time Machine. We understand that Apple regards this as a system bug and is working on a fix; it's certainly something we'd like to see – soon!
If you've installed any antivirus software on your Mac, you'd do well to exclude your backup disk from virus scanning, as this can slow down Time Machine – the files have, after all, already been scanned.
Check the Help section of your chosen antivirus product for details on setting exclusion policies.
If you're using Aperture, Apple's image management and processing software, Apple advises that you should have at least Mac OS X 10.5.3 if you intend to use Time Machine to back up your Aperture Library. The only reason given by Apple for this is that "earlier versions of Leopard did not provide full compatibility between Time Machine and Aperture".
Using certain characters in your Mac's name in the Sharing System Preferences pane can cause some backups not to appear when you attempt to restore a file using the Time Machine interface. You should therefore go to System Preferences > Sharing and make sure that the Computer Name field contains only numbers and upper or lowercase letters.
Backing up multiple Macs
You can use a single disk to back up multiple Macs, as Time Machine will create a different backup folder for each. If you're moving the same disk between a number of Macs or sharing a Time Capsule, you should make sure that each Mac is given a different name in System Preferences > Sharing, using the guidelines above.
You can, incidentally, make backups across an Ethernet or AirPort network using a FireWire or USB 2.0 drive attached to one of your Macs: just remember to enable Personal File Sharing in System Preferences > Sharing. This is probably not the most efficient way of backing up, as network traffic is greatly increased during backups.
If you dismissed the Time Machine dialogue the first time you attached your external disk, no problem. Once you're ready to start backing up, go to Time Machine's System Preferences pane, where you can choose your backup disk and get started. We'll show you how in our step-by-step guide later on.
You don't have to back up every single item on your Mac's hard disk: for instance, you might want to exclude all system files. This makes sense if you want to conserve space on your backup disk; you can always use either the installation discs that came with your Mac or a bought copy of Leopard to install a clean copy of your system after a system crash. You won't, however, have the option of using your Time Machine backup to perform a full system restore should the need arise.
Creating your first backup
When Time Machine creates its first backup, it takes quite a while to do it. This is because it's making a complete copy of everything you've chosen to back up. After this initial backup, Time Machine will make copies only of those files that have been changed since the previous backup – a so-called 'incremental' backup.
Time Machine makes backups every hour, as long as your backup disk is attached to your Mac and your Mac is turned on and active (that is to say, not in Sleep mode). In fact, it takes backups every hour out of the previous 24 hours, daily backups to cover the past month and then every week until your backup disk is full. Unless you're happy to overwrite your oldest backups, you'll need to attach another disk once your current one is full and choose it in System Preferences > Time Machine – just make sure it has a different name to the previous one. If Time Machine is unable to take a backup it will resume its duties the next time your Mac is awake and the disk is again available.
Depending on the way you like to work, you might feel that one backup every hour is too often (or not often enough). To change this, open Terminal (from Applications > Utilities), and type the following (all on one line), then hit the [Enter] key:
sudo defaults write /System/Library/LaunchDaemons/ com.apple.backupd-auto StartInterval -int 3600
Replace 3600 with your desired backup interval in seconds. For example, you could set a two-hourly backup like so:
sudo defaults write /System/Library/LaunchDaemons/ com.apple.backupd-auto StartInterval -int 7200
If you'd rather not use Terminal, TimeMachineEditor (free from http://timesoftware.free.fr/timemachineeditor) has a much friendlier graphical interface, and enables you to set either short backup intervals measured in hours or schedule daily, weekly or monthly backups to take place at specific times. You can also set up combinations of daily, weekly and monthly backups.
The Time Machine icon is usually located in the Dock; if you can't find it there, try your Mac's Applications folder. The first thing you should notice when you launch it is the vertical timescale to the right of the screen. This enables you to navigate back and forth through Time Machine's snapshots of your system using the large arrows near the timescale – you should see your deleted files repopulate the window from past backups. Once you've found the file you're looking for, click the Restore button, and it will be returned to the appropriate place in your current system.
When you want to restore some types of file, your best starting place is the folder or Mac OS X application from which you deleted it. So, if you deleted an email, launch Mail; for a photo launch iPhoto.
Time Machine is integrated with every aspect of Leopard, so when you launch it, those application windows will remain open, allowing you to search for your lost files. The same thing will happen if you navigate to the folder from which you deleted a misplaced file. Alternatively, if you remain in Finder as you launch Time Machine, a new Finder window will open.
Time Machine and Spotlight
As you might expect, Time Machine can work alongside Spotlight, Mac OS X's desktop search technology, in order to make it even easier to find that deleted file. Simply open a new Spotlight window using the default keyboard command (O+ C+[Spacebar]), and add as many search criteria as you need to, both by entering text in the Spotlight field in the top right- hand corner, and by using the + button to add more information, such as the date the item was created.
Note that you can't start up your Mac from a Time Machine backup. Instead, you'll need to use your Leopard installation disc, either by inserting the disc and rebooting while holding down the [C] key on your keyboard, or by double-clicking the Install Mac OS X icon when the disc mounts on the Desktop. If you think your problem might be a faulty startup disk, we'd strongly suggest you at least use the First Aid section of Disk Utility (from the Utilities menu in the Mac OS X installer) to verify and repair the disk. Sometimes, zeroing out the data on the disk will eliminate file system conflicts, and allow you to start afresh.
Once you're satisfied that your startup disk is okay, restore your system by going to Utilities > Restore System from Backup. Use the onscreen instructions to select the Time Machine backup you want to use to resurrect your system.