Time Machine backup: USB to Airport Extreme

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Time Machine backup: USB to Airport Extreme

I have a new 3TB drive purchased for use as a Time Machine backup drive. At the same time, I replaced my old, first generation Airport Extreme with a newer Airport Extreme that will allow me to use an external drive for Time Machine. I did my first backup to the new drive connected by USB. Internal SSD in MacBook Pro contains 395GB. Took about 20 hours for that first backup. Now I've connected the drive to the Airport Extreme. I was hoping that Time Machine would recognize the existing backup but, apparently it won't. Is there any way to avoid another first backup? What is the relative speed of the Airport Extreme wifi connection and USB 3?

MacBook Pro with Retina display, OS X Yosemite (10.10.4)

Posted on Jul 31, 2015 7:40 PM

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Answer 1

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Linc Davis

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Jul 31, 2015 8:44 PM in response to rdosh

Network backups are in a different format than local backups. You have to start over.

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Answer 2

rdosh Author

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Aug 1, 2015 3:53 AM in response to Linc Davis

Thanks.

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Answer 3

Aug 1, 2015 5:25 AM in response to rdosh

What is the relative speed of the Airport Extreme wifi connection and USB 3?

Very Slow.

First, the USB port on the AirPort Extreme....or any of the other Apple routers is not USB 3.0.....it's USB 2.0. And, the 2.0 port on the AirPorts runs at about half the speed of a USB 2.0 port on a computer.....due to processor limitations on the AirPort router.

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Answer 4

rdosh Author

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Aug 1, 2015 5:50 AM in response to Bob Timmons

Bob, my question really was to compare the speed of backing up over my Airport network (presumably, wireless G) with backing up to the same drive connected to the computer by USB 3. I already answered my own question and it appears to be almost a full order of magnitude (54 mbps vs 480 mbps). I had been backing up by Time Machine just once a week. And that was backing up my almost full 500 GB internal SSD to an external 500 GB USB (2?) drive. (Amazing how long that really worked.) Now, I have the 3TB USB 3.0 drive but have it connected to my Airport Extreme thinking that I'd back up more often. However, when I have a lot of new 20 megapixel photos to be backed up I think I'm going to be very disappointed in the speed of backing up over the network.

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Answer 5

Aug 1, 2015 6:06 AM in response to rdosh

(54 mbps vs 480 mbps)

So, your wireless network runs at "g" wireless speeds (54 Mbps)? Obviously, if you are backing up over wireless, the backup is not going to be any faster than the wireless connection will allow.

The fastest speed that you will ever get using the USB 2.0 port on the AirPort routers is going to be in the 220-240 Mbps range.....assuming your wireless will provide that signal speed.

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Answer 6

rdosh Author

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Aug 1, 2015 8:53 AM in response to Bob Timmons

I'm just weighing whether I really want to use a network backup or not. If I use a network backup, I'll backup more frequently. But, if I use a direct USB 3.0 connection to backup, it will be much faster but I probably won't backup more than once or twice a week. Once I got past the relative speed question, I can only answer the underlying question myself. But, I was also thinking out loud here in case there were any network vs direct USB backup factors that I have not been considering. Backing up via Airport network is new to me.

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Answer 7

Aug 1, 2015 9:13 AM in response to rdosh

In addition to being much slower, network backups are a lot more complicated in terms of the network signal path. If you then add wireless , which is not nearly as reliable as a direct wired connection to the mix and the whole thing becomes suspect.

So, if reliability is your goal....not even taking speed of backups into consideration.....the direct computer to USB hard drive is pretty much of a no brainer.

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Answer 8

rdosh Author

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Aug 1, 2015 11:20 AM in response to Bob Timmons

Thanks. I may well switch back to a direct-to-drive backup. I'm also considering using both. Perhaps more frequent backups over the network and a more reliable direct backup to a different drive once or twice a week. I appreciate your input.

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