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I have several Macs (10.6) on a wireless home network and want to add a network HDD, primarily as a drive for Time Machine to back up to. Having heard bad things about Apple's Time Capsule, I'm currently looking at buying a Western Digital 1TB NAS and connecting it via ethernet cable to a wireless router on the network. I have no experience using Time Machine, although it looks pretty straightforward.

Before trying this, I'd like to know:

1) Will this actually work? WD claim their drive is 'Time Machine ready', but how should it be formatted/partitioned? Has anyone had experience doing this? Is there a better make of drive for around the same price?

2) Assuming it's ok for backups, can I also use part of the drive to store my iTunes library (and take the pressure off my iMac's little 80Gb HDD)? If so can I use the same partition as the backup? Ditto for manual archiving of some old movie files...


Edit: I've just seen this other post, which has some good things to say about the Western Digital MyBook World Edition...

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2 Answers 2

I don't have a WD but my LaCie D2 Network 2 also has Time Machine support, and it works well. You don't partition or format it, you just flag a share as needing to support Time Machine and the device takes care of everything for you.

As for sharing a partition between backup and iTunes, that's not a good idea because Time Machine will eventually use all available drive space for backups, using any extra space to increase the number of versions of files it can keep. The LaCie drive deals with this by letting you create as many shares as you want, and putting a quota on the share available to Time Machine so that it won't take over the rest of the disk. I'm nowhere near my quota so I don't know how well it works though. Presumably WD has done something similar.

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It is worth adding that Time Machine support from anyone other than Apple is unofficial, and there's no guarantee that it won't break in future versions of MacOS. –  David May 20 '11 at 17:21
Thanks David, this is great stuff. I'm a little worried about noise: does the LaCie have a fan of any kind? –  Richard Inglis May 20 '11 at 17:35
There's no fan; LaCie uses solid metal cases to utilize conductive cooling. –  David May 20 '11 at 17:39

From reading your question and the answers so far, I'd like to clarify some terms in hopes to help you find what will help you best. Having a hard-drive manufacturer say their drive is Time Machine ready simply means that it is already formatted for the Mac. But you can always bring any external drive and format it for the Mac using Disk Utility. Of course, doing this will erase the drive, so keep that in mind.

Once you have your hard drive, then the next thing to clarify in the discussion is Time Machine Vs. Time Capsule. Time Machine is a Mac OS X feature that will back up your data in the background. However, this feature only works with a hard drive physically attached to your mac. As far as I know, it will not work over a network.

On the other hand, Apple sells a product called the Time Capsule (do not confuse this with Time Machine). The Time Capsule is a wireless network hard drive that Time Machine actually supports. Adding a Time Capsule to your network would be the only official way to use Time Machine over the network.

Finally, regardless of whether or not you're using a Time Capsule: When you use Time Machine on a hard drive, you can continue to use the remaining space on the hard drive for storing whatever you want (like your iTunes library in your example). In other words, using Time Machine will not make use of this drive exclusive to Time Machine. The only thing to keep in mind is that Time Machine will create a folder at the root of the drive where it will keep its backup sets. Leave that folder alone and you should be fine. :)

My current set up consists of a 1 TB Western Digital hard drive attached over USB and backing up using Time Machine. Time Machine will create sets for each one of the last 24 hours, each one of the last 30 days, and each month until it runs out of space. In order to make the best use of the drive, and this is a tip I wanted to share with you, I have configured Time Machine via System Preferences to ignore the Downloads folder and my iTunes Podcasts folder, which have tons of data that I do not need to back up.

You may also want to consider looking at a Pogoplug. I do not own one (yet), but it looks like a compelling alternative to create a shared media hard drive on my local network.

Hope this helps sort things out.

Update: As it was pointed out on this thread, there is a way to get Time Machine to work over a network. It involves modifying preferences files via the terminal and while it is not a difficult process, it is evidently not an officially supported method to use Time Machine--otherwise, the System Preferences UI would allow you to select network drives other than Time Capsules. The name of the configuration value that must be modified, "UnsupportedNetworkVolumes", hints at this as well.

So while the answer to the question "Is it possible?" seems to be yes, my advice for the tweak suggested on this thread is to use it at your own risk. I can't help to think that there could be a technical reason why Apple has not allowed network drives to be used for Time Machine out-of-the-box. Perhaps they haven't obtained optimal results. Perhaps a Time Capsule is better designed for working with Mac OS X and the way Time Machine itself it designed. Or... and this is also a possibility, Apple is only blocking network drives to sell more Time Capsules.

In any event, if you experience excellent performance with Time Machine using an officially unsupported network drive, please post to this thread and let us know how it works. Good luck.

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"... it will not work over a network." - really? Lots of other people seem to be doing so; eg, from Wikipedia: "For backups to a network drive, Time Machine allows the user to back up Apple Macintosh computers through Apple's AirPort networking, and supports backing up to normal network attached storage devices or servers", or this: hints.macworld.com/article.php?story=20080420211034137 –  Richard Inglis May 20 '11 at 22:22
And from the Western Digital website: "Compatible with Apple Time Machine. Mac computer users can utilize all the features of Apple Time Machine backup software to protect their data. Back up all your Macs wirelessly to one location over your WiFi network." That seems pretty unambiguous... –  Richard Inglis May 20 '11 at 22:43
I should revise my answer a little bit. The point I was hoping to make (as I state on the very next paragraph from the one you quoted me from) is that using a Time Capsule is the only official method. By that, I mean that is the one way you could achieve a network backup out-of-the-box using the regular UI on System Preferences. –  Christian Correa May 23 '11 at 19:55
I'm using a Synology DS411j NAS product with Time Machine for network backup out-of-the-box using the regular UI on System Preferences. I did not have to do the "UnsupportedNetworkVolumes" workaround that you mentioned above. –  Lee Jun 25 '11 at 22:08

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