6.4. Time Machine
As the old saying goes, there are two kinds of people: those who have a regular backup
system—and those who will.
You'll get that grisly joke immediately if you've ever known the pain that comes with
deleting the wrong folder by accident, or making changes that you regret, or worst of all,
having your hard drive die. All those photos, all that music you've bought online, all your
email—gone.
Yet the odds are overwhelming that at this moment, you do not have a complete, current,
automated backup of your Mac. Despite about a thousand warnings, articles, and
cautionary tales a year, guess how many do? About four percent. Everybody else is flying
without a net.
If you don't have much to back up—you don't have much in the way of photos, music, or
movies—you can get by with burning copies of stuff onto blank CDs or DVDs (Chapter
11) or using the .Mac Backup program described at the end of this chapter. But those
methods leave most of your Mac unprotected: all your programs and settings, not to
mention Mac OS X itself.
What you really want, of course, is a backup that's rock-solid, complete, and automatic.
You don't want to have to remember to do a backup, to insert a tape, to find a cartridge.
You just want to know that you're safe.
That's the idea behind Time Machine, a marquee feature of Leopard. It's a silent, set it-
and-forget-it piece of peace of mind. You sleep easy, knowing there's a safety copy of
your entire system: your system files, programs, settings, music, pictures, videos,
document files—everything.
Yes, Time Machine has a fabulous, gorgeous, sci-fi, space-themed recovery mode, where
it looks like you're flying back in time to retrieve files, folders, or disks from the past.
With luck, you'll never need it. But if your luck runs out, you'll be so happy you set Time
Machine up.
6.4.1. Setting up Time Machine
Here's the bad news: Time Machine requires a second hard drive. That's the only way to
create a completely safe, automatic backup of your entire main hard drive.
That second hard drive can take any of these forms:
• An external USB or FireWire hard drive.
• Another internal hard drive.
• A partition of any one of those drives.
The hard drive of another Leopard Mac on the network. You must first mount its drive on
your screen (Chapter 13).
Tip: It's perfectly OK to back up several Macs onto the same external hard drive, as long
as it's got enough room. You can also back up onto a hard drive that has other stuff on it,
although of course that means you'll have less room for Time Machine backups.
In all cases, the backup disk must be bigger than the drive you're backing up (preferably
much bigger).
Here's what you can't use as the backup disk:
• An iPod.
• The iDisk.
• Your startup drive.
• CDs, DVDs, flash drives, or any other kind of removable disk.
Note: If Time Machine doesn't recognize the drive you've given it, the drive might not be
a standard Mac-formatted hard drive. That's a gotcha that befalls many a Mac fan who
buys a new hard drive for backup purposes; many new drives come in Windows format,
which Time Machine doesn't recognize.To make a new, empty drive like this ready for
Time Machine, open Disk Utility (Section 10.30.9). Click the drive's name, click the
Erase tab, choose Mac OS Extended (Journaled) from the Volume Format pop-up menu,
and then click Erase.
Sure, it sounds like an Apple plot to sell more hard drives. But you'd be surprised at how
cheap hard drives are. At this writing, you can buy a 300-gigabyte internal hard drive for
under $90, for goodness' sake, or an external 500-gig drive for $125—and hard drive
prices-per-gigabyte only go down.
The first time the Mac sees your second hard drive, it invites you to use it as Time
Machine's backup drive (Figure 6-5, top). That could be the moment you connect an
external USB or FireWire drive, or the first time you turn on the Mac after installing an
internal drive.
If you click Use as Backup Disk, you're taken immediately to the Time Machine pane of
System Preferences (Figure 6-6, bottom). It shows that Time Machine is now on, your
backup disk has been selected, and the copying process has begun. The Mac copies
everything on your hard drive, including Mac OS X itself, all your programs, and
everyone's Home folders.
Note: Time Machine doesn't use any compression or encoding; it's copying your files
exactly as they sit on your hard drive, for maximum safety and recoverability. On the
other hand, it does save some space on the backup drive, because it doesn't bother
copying cache files, temporary files, and other files you'll never need to restore.
Your total involvement has been one click. And that, ladies and gentlemen, is the easiest
setup for a backup program in history.
Now go away and let the Mac do its thing. The first backup can take a very long time—
hours—as the Mac duplicates your entire internal hard drive onto the second drive. The
Mac may feel drugged during this time.
Figure 6-5. Top: The Mac has just encountered a second hard drive. Time Machine
still works if there's other stuff on the drive, but life is simpler if you don't use that
drive for anything but Time Machine. The more space Time Machine has to work
with, the farther back in time you'll be able to go to recover deleted or mangled files.
Bottom: The backup has begun. You know that because you see both a progress
message and the symbol that appears next to the backup drive's name in your
Sidebar.
6.4.2. How the Backups Work
From now on, Time Machine quietly and automatically checks your Mac once per hour.
If any file, folder, or setting changes, it gets backed up at the end of the hour. These
follow-up backups, of course, take very little time, since Time Machine backs up only
what's changed.
So, should disaster strike, the only files you can lose are those that you've changed within
the last 59 minutes.
Tip: And even then, you can force more frequent backups if you want to. Any time you
want Time Machine to update its backup before the hour's up, Control-click (or right-
click) Time Machine's icon on the Dock. From the shortcut menu, choose Back Up
Now.You can pause the backup the same way—if you need to use the backup drive for
another quick task, for example. Control-click the Dock icon and then choose Stop
Backing Up. (Don't forget to turn the backing-up on again when you're finished.)
By the end of the day, you'll have 24 hourly backups on that second disk, all taking up
space. So at day's end, Time Machine replaces that huge stash with a single daily backup.
You can no longer rewind your system to 3:00 p.m. last Monday, but you can rewind to
the way it was at the end of that day.
Similarly, after a week, the dailies are replaced by an end-of-week backup; after a month,
the weeklies are replaced by a single end-of-the-month backup. Now you can't rewind to
October 24, but you can rewind to November 1. (Apple assumes that it won't take you a
whole month to notice that your hard drive has crashed.)
Tip: You can see these backups, if you want. Open your backup drive, open the
Backups.backupdb folder, and open the folder named for your computer. Inside, you'll
find a huge list of backup folders, bearing names like 2007-12-22-155831. That's the
backup from December 22, 2007 at 15:58 (that is, 3:58 p.m.) and 31 seconds.
The point is that Time Machine doesn't just keep one copy of your stuff. It keeps multiple
backups. It remembers how things were in every folder—not just yesterday, but last
week, last month, and so on. It keeps on making new snapshots of your hard drive until
the backup drive is full.
At that point, the oldest ones get deleted to make room for new ones.
FREQUENTLY ASKED QUESTION
The End of Time
What happens when my backup drive gets full?
Good question.
The whole idea of Time Machine is that it preserves multiple backups, so that
you can rewind a window or a drive not just to a backup, but to any date in the
past. The bigger the hard drive, the farther back those monthly backups are
preserved.
Eventually, of course, your backup drive runs out of space. At that point, Time
Machine notifies you and offers you a choice.
You can keep using that drive; Time Machine will begin deleting the oldest
backups to make room for newer ones.
Or you can install a new Time Machine backup drive. New backups will go on
that one; your older backups will still be available on the original drive.
If you ever need to retrieve files or folders from the older disk, Control-click
(right-click) the Time Machine icon in the Dock; from the shortcut menu,
choose Browse Other Time Machine Disks. In the list of disks, choose the older
one. Then click the Time Machine icon on the Dock to enter the Restore mode.
Tip: Ordinarily, Time Machine alerts you when it has to start deleting old backups. If
you'd rather have it just do it without bothering you, open System Preferences; click Time
Machine; click Options; and finally turn off "Warn when old backups are deleted."
By the way, if a backup is interrupted—if you shut down the Mac, put it to sleep, or take
your laptop on the road—no big deal. Time Machine resumes automatically the next time
you're home and connected.
6.4.3. Changing Time Machine Settings
Time Machine has three faces in Leopard. There's the application itself, which sits in
your Applications folder; click it to enter Restore mode. There's its Dock icon; its
shortcut menu has a few commands (like Back Up Now) that aren't available anywhere
else.
And then there's its System Preferences pane, where you adjust its settings (Figure 6-6).
To see it, choose System Preferences, and then click Time Machine. Or choose
Time Machine Preferences from Time Machine's Dock icon.