As far as backup strategies go, Time Machine is a pretty good addition to your backup strategy. You get hourly backups, can go back and retrieve accidentally-deleted files and can even restore your system from it. At both home and work, I use it as part of my backup strategy, filling in the spaces between regular clones of my system. In fact, the only thing I dislike about Time Machine is how long it takes to create its initial backup if you’re backing up to a shared drive over a network.
Recently, I took the opportunity to centralize the majority of my storage in my home to drives attached to an older MacBook Pro. As part of this project (which is the topic of a different article down the road), I put a 2.0TB drive in an older USB 2.0 miniStack, and wanted to use this as the Time Machine drive for my current MBP. The problem was that—regardless of whether I connected to that drive via WiFi or via Ethernet—Time Machine kept telling me that a backup of the approximately 250GB would take around a week or more to make.
Obviously, this was not acceptable.
Drawing from various sources on the Internet (where, apparently, there are a large number of people with similar complaints), I was able to paste together a solution that enabled me to get Time Machine’s initial backup time to reduce from over a week to just under two hours.
Note: I performed these steps in OS X 10.8.3; while this certainly should be possible with earlier (and I would assume later) versions of OS X, your mileage may vary.
For this method, there will be a bit of swapping of drives and computers, and if you’re not paying attention, it may get a little confusing. To help keep things straight, here are the terms I’ll use throughout the article.
- TM Drive - This is the drive we’re going to use for our Time Machine backups.
- Server Mac - This is the computer that—at the end of things—will have the TM Drive Connected to it. Keep in mind that once things are completed, this computer needs to always be on, as Time Machine will connect to it regularly.
- Client Mac - this is the Mac that you want to back up over the network using Time Machine.
Step 1. – Start with a freshly-formatted Time Machine Drive.
The first part of all this is to make sure your Time Machine drive/partition is empty. At the very least, make sure there are no Time Machine backups from the Server Mac on it. I tried doing this after backing up the Server to the TM Drive first, but things got ugly quickly. If you’re going to back the Server Mac up to the same drive you’re backing up your Client Mac(s) to, you will need to set that up after you set up Time Machine on the Client Macs.
Step 2. – Share your Time Machine Drive on your Network
Attach your TM Drive to the Server Mac. Enable File Sharing on your Server Mac and add the Time Machine drive to the list of “Shared Folders” by cliking the “+” button and selecting it from the dialog box.
Step 3. – Mount the Time Machine drive via your network.
On the Client Mac, connect to the Server Mac and select the TM Drive you’re going to back up to. The drive should now appear on your desktop, similarly to as if you had it connected directly.
Step 4. – Select the networked drive in Time Machine.
Open the Time Machine preference pane on your Client Mac, make sure it’s set to “On” and click the “Select Disk” Button. You should see the networked TM Drive as one of your choices. Select it and click the “Use for Backup” button. You will likely be asked for a username/password for an account on your Server Mac. However, if you added the drive to the “Shared Folders” list in Step 2, you should be able to simply connect as Guest with no issues.
Step 5. – Start the initial backup normally.
At this point, the backup process will begin. Time Machine will create a temporary disk image as it starts the backup process. Depending on your particular network setup, this may take a while. Once the Time Machine volume is set, the image will change to a standard Sparse Disk image with the name of your computer as its name (computername.sparesebundle) and your data will begin to transfer over.
Step 6. – Stop the initial backup.
Once data starts to transfer, you’ll see how much is going to be moved and how long it should theoretically take (usually several days, depending on how much you have to transfer). Immediately cancel the backup by clicking the little “x” next to the progress bar. The disk image Time Machine made should still remain on your external drive.
Step 7. – Attach the Time Machine Drive to the Client Mac directly.
Once the Time Machine backup has been halted, unmount the TM Drive from the Client Mac by simply dragging it to the Trash. Then, do the same on the Server Mac, where the drive is connected directly. Once it’s unmounted there, you can safely disconnect the TM drive from the Server Mac and attach the TM Drive directly to the Client Mac.
Step 8. – Complete the initial backup.
Once the TM drive is mounted on the Client Mac’s desktop, open up the Time Machine preference pane again, and reselect the TM Drive from the list. In later versions of OS X, it may appear twice; simply select the “new” listing and DO NOT use the “Remove Disk” option for the existing “Backup Disk” listing. The backup should complete a lot faster now (usually dropping from several days to just a couple of hours). Once the initial backup has completed, use the Time Machine app in the Dock or the Time Machine menu bar item to enter the Time Machine interface. You can then exit Time Machine and unmount the drive from the desktop.
Step 9. – Reestablish the Time Machine Drive as a networked drive.
You can now reattach the TM Drive to your Server Mac. Once it shows on the desktop, you can then reconnect to it with your Client Mac like you did in Step 3. Once the drive is mounted, you can then re-select it as your Time Machine drive, like you did in Step 8.
Once again, enter the Time Machine interface from either the Dock or menu bar item and then exit again.
Step 10. – Your Client Mac is now ready to back up over the network.
At this point, you can unmount your TM Drive from your desktop. Now, when it’s time for Time Machine to back up, it will automatically mount the disk image over the network, back up to it, and disconnect again.
If you have other Macs you would also like to back up over the network, simply repeat Steps 3 through 9 for each Mac you want to back up.
The more copies of your data you have, the more prepared you are in the event of drive failure. Now that we’ve sped up that initial backup, we’ve removed the most inconvenient hurdle to setting up Time Machine, we have a convenient way to back up over your local network that’s already built in to OS X.