Time Machine, Airport Extreme, USB drive help

Discussion in 'Mac Basics and Help' started by Piercey, Jan 29, 2010.

  1. Piercey macrumors newbie

    Feb 1, 2008
    I've been using a 500gb external usb drive with Time Machine for some time now. I recently bought an Airport Extreme router so I could move all of my external drives onto my network. The idea was to continue using the 500gb drive with TM, just over the network.

    But TM wanted to start all over like it had never used the drive before now that it was on the network. So I reformatted the drive and let TM do its thing but at the end of the 1st backup it said it had failed.

    So my question is what am I doing wrong? Or better yet is there a way to get that 1st huge backup over with? Can I plug the usb drive into my computer and then move it over to the network and get it to pick up where it left off?

    Any help would be great.

    Thanks in advance!

  2. Makosuke macrumors 603

    Aug 15, 2001
    The Cool Part of CA, USA
    I'm fairly certain that Time Machine behaves differently when it's using a network versus local volume. With physically attached drive it takes over the whole partition on the drive. With a network drive, it creates a sparse bundle disk image on the drive, mounts that and backs up to it. This allows Time Machine to use its fancy low-level algorithms to track changes and save space regardless of what format or server time the drive is coming in from.

    So there's no way to do a direct-connect backup first. That said, you can at least connect to the Airport Extreme via a physical ethernet cable for the first backup, which will go either somewhat faster than wireless (if you have an older one with 100Mbit ethernet) or drastically faster (if you have a newer gigabit one).

    That said, when I tried to run that exact setup with a new-ish Gigabit AEBS and Western Digital MyBook 500GB drive, it didn't work properly. I could get a few good backups done, but eventually something would end up corrupting the Time Machine volume, requiring me to start over completely. I'm pretty sure the problem was that the AEBS just didn't have the horsepower to handle that much data throughput, so eventually hiccuped and corrupted the backup.

    The exact same setup, with the exact same hardware, has worked perfectly for months when the drive is connected to a Mac Mini running as a server, so the problem obviously wasn't with the network or hardware.

    So the bottom line is that turning off wireless on the Mac being backed up and connecting via an ethernet cable for the initial backup will get it done faster, but based on my personal experience I don't think that setup is going to be reliable in the long run.
  3. Piercey thread starter macrumors newbie

    Feb 1, 2008
    I just went through the entire process today. Starting around 2pm and finishing about 9:30 pm with it plugged in via an ethernet cable and got the same error as when I did it via over wireless.

    Is this a lost cause? grrrrrr :mad:

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