I wrote about backing up your Mac and PC in January of 2008, and I said Time Machine was a great way to back up your Mac. A year later, I still think so, though I have some reservations.

There are three ways to back up your Mac with Time Machine. There used to be only two, but thanks to Drobo Apps, we now have three. I’ll list them in descending order, sorted by backup speed. Here they are:

To External Hard Drive (USB, Firewire, eSATA)

This one’s easy, and it’s the fastest way. You get a dedicated external hard drive, you connect it to your Mac, and you let Time Machine do its thing. You can leave it connected all the time, or you can disconnect the hard drive and only back up when you want to. Time Machine won’t complain unless you haven’t backed up for a few days.

This is the backup strategy I’ve come to use, and believe me, it’s the one that gives me the least amount of headaches. I have a 500GB LaCie Mini hard drive that connects over USB. I plug it into my laptop, and within minutes, my backup is done.

Keep in mind that I’m a photographer, and I also shoot short videos every once in a while, so it’s pretty much a given that I’m backing up gigabytes of data every time. When the backup’s done, I eject the drive and put it away. This way I’m not bothered by hourly backups, which I don’t need.

To External Hard Drive via Time Tamer

Go download Time Tamer, a very handy little app created by the folks that make the Drobo, and you can create an image file on your Drobo that is limited to twice the size of your Mac’s hard drive. This is useful because there is no other way to control the size of the Time Machine backup sets. There’s is no way to set a quota via its System Preferences panel, and so it’ll keep balooning until it fills the backup drive. Obviously, when you have a Drobo or another larger drive, that’s a problem.

I for one don’t want to fill up my Drobo with Time Machine backups — I have other more important uses for it. I did, however, want to limit the amount of external drives that sat on my desk, and thought I could eliminate one of them by using Time Tamer with my Firewire Drobo. Did that for a few months, but I can tell you it’s not optimal, at least not for me. It boils down to the amount of data one has to back up, really.

As it turns out, the throughput when writing to the image file just isn’t fast enough when you work with several hundred megabytes or more. Even though writing to the Drobo is usually a fairly fast operation, somehow writing inside the image file isn’t. From my own experience, it would sometimes take a whole hour to do an hourly backup, which meant that as soon as one backup finished, another would start.

To make things more annoying, the throughput to the Drobo itself, and my Mac’s general peppiness, were also affected negatively during backups. Everything churned at a slower pace. Getting at my photos or other files stored on the Drobo was a pain. If I happened to be playing a movie and a backup started, playback would stutter or stop for a few seconds. It just wasn’t a feasible way for me to work, so I stopped doing this and returned to doing my backups directly to a dedicated external hard drive.

To wireless or networked hard drive (such as Time Capsule)

This will usually be the slowest way to back up your Mac via Time Machine. Think about it: you’re going to be pushing your bits via WiFi, and even though your hardware may be “n” specs instead of “b” or “g”, you’re still not going to get above 50 Mbps at best. Realistically, you’re looking at speeds somewhere between 15-45 Mbps, which is less than Fast Ethernet (100 Mbps) and nowhere near Gigabit Ethernet (1000 Mbps).

For comparison purposes, I have observed transfer speeds which approached USB 2.0 speeds when using a direct, wired, Gigabit Ethernet connection between two Macs (MacBook Pro and iMac G5). If you have a wired Gigabit network at home, this might be the only way to actually get decent backup speeds with Time Machine without needing to use USB or Firewire hard drives. But if you’re using WiFi, your transfer speeds are going to be anywhere between 15-20 times slower than Gigabit speeds, which means you’ll be sitting there a long time waiting for your backups to finish, should your backup set be anything over 100-200 MB.

When Time Capsule came out, I was tempted to buy it, just like I bought the Apple TV, only to regret that later. I’m glad I didn’t end up spending my money on Time Capsule, because it just isn’t suitable for me, or for anyone with larger backup sets. It certainly looks good, but that’s about all it does and all it’ll do until WiFi speeds approach Gigabit speeds.

Takeaway message

When one of my friends shared an article from Louis Gray via Google Reader, where he complains about how slow it is to back up to Time Capsule, was I surprised? Given all I’ve written above, do you see why I wasn’t?

Do the smart thing: if you’re using Time Machine, get a little portable drive like I did and run your backups that way. They’ll be fast, and you’ll be the one deciding when to back up, not Time Machine. I don’t know when Apple will decide to give us more configuration options for Time Machine, but until they do, those who care about their time should back up directly to an external drive.