I plan on migrating data from my present Mac Pro to the new iMac 5K Retina when the new machine arrives using Target Disk Mode.. The MP has four internal drives:

Bay 1: Time Machine backup
Bay 2: Storage drive for large files (at this time, redundant)
Bay 3: My default startup drive with OS 10.6.8
Bay 4: Clone of Bay 3.

When I start up in TDM, which drive will Setup Assistant in the new iMac see? I want to migrate from Bay 3.

If my memory serves me, and if the status remains quo, you'll have the option to select either Bay 3 or Bay 4.

I don't think your TM backup will show up, because it's not a bootable volume.

You may find Move your data to a new Mac helpful.

There will be an option to restore from a Time Machine backup offered as well.

I hedged, because I've never run into the situation; thanks for correcting me.

(Why did my "TM" turn into "â„¢" in your quote?)

Edit: My bad for not reading the doc to which I linked.

Hopefully, both of you are right. If it's ambiguous, I still have two alternatives: Migrate via ethernet or install the desired drive into a Thunderbolt enclosure and migrate from there. I'll post back to let everyone know how it goes.

I doubt that you'll need to fall back on your alternatives, Jon.

Setup Assistant has given me a choice of boot drive, cloned partition, and external HD when I've used it. (Time Machine is outside of my experience.)

Sounds like a SWEEET machine... ENJOY!!!

Because in System Preferences > Keyboard > Text I have the characters TM setup to substitute â„¢. That seemed a good idea at one time, but it has become annoying when using TM to refer to Time Machine. I will change that right now.

I've got the same pref set in System Preferences > Language & Text > Text, but it has never, ever worked for me, and I've long since forgotten that it's even an option.

I don't recall if that was happening in Mavericks or not, but it sure happens in Yosemite.

I would expect to see 1 (as it has backups that can be restored from which the migration can use as a source), not 2 (since it has no os/user folders), 3 (probably where you want to migrate from) and 4 (since it is a copy of 3, which may be a little confusing, hopefully you named it different than 3)

At this point, I'm considering using migrating via ethernet rather than TDM. The salesperson at Apple told me that TDM (via Firewire - Thunderbolt adapter) may be the faster of the two, but according to Topher Kessler's reply to this question, ethernet is faster. I consulted a technology student (working on his Masters) who was informed by his professor that ethernet is faster.

Opinions, anyone?

Not an opinion, but I've always heard that ethernet is faster (not to mention that you won't have to spring for a $30 adapter), but out of curiosity, how much data must you migrate that it's such a burning issue?

I'll be migrating about 115 GB. It's only a "burning issue" if I use a super drive.

BTW, I already bought the adapter. Even if I don't use it for this purpose, I'll need it to connect my Nikon scanner to the iMac.

I've never moved that much data with Migration Assistant, but I've dragged & dropped that much from my internal to my external (and vice-versa) via FireWire 400 in a bit over an hour.

That's why I asked...to maybe put some perspective on what you'll be facing.

It's by no means going to be a terribly long affair, no matter how you do it.

Edit: Qualifying that... My experience has been with my iTunes Library, which comprises about 600 relatively large files; if you're migrating a whole bunch of small files, all bets are off.

When I got my Mac Pro, I migrated about 40 GB from my G4 DP 450 in about 90 minutes via FW 400. The speed should be much faster with my present setup. At any rate, I'll set it up in the morning and let it run while I do other chores. It shouldn't be a big deal. I have a lot of photos (large files) plus small ones. We'll see...

I would say it depends. For lots of little files, firewire is usually faster, due to faster processing of file overhead and direct disk i/o. If you have good network conditions, newer macs on both ends, and mostly large files, gigabit is probably going to go faster.

Sounds like six of one, half a dozen of the other. I'll probably go with ethernet.