Hi, I have a couple of questions on Time Machine setup and how it works.

My current computing config is a mac mini, windows 7 laptop (my wife's), 2 x macbook, and a yet to be purchase macbook pro or air, all connected to the Internet via a pair of airport extremes (long story).

Up to now, I only backed up my mini via a USB attached drive, but I want to start backing up the MacBooks & macbook pro/air as well. I have a USB hub attached to the airport to share a colour laser printer and some old external drives that I will retire at some point.

I just bought a new 3TB GoFlex Desk drive that I have connected to the mini for now.

Now for the questions - first, I moved my current backup drive to the airport USB port, Time Machine thought it was a new drive and started backing up from scratch - why did it do that when the files are already there and it's the same machine (the mini) that is being backed up? (N.B. I moved the drive back to the mini for now and things are back to normal, TM recognized the existing backup - i tested a recovery from January)

Secondarily to this - how does one move a current TM backup to another drive (like my 3TB for example? Do I have to tweak config files or something like that? This seems like a bit of a gap in functionality.

Last, what would a proper approach be to the larger backup picture? Should I attach the 3TB drive to my Airport or leave it on the mini? Would it perform better one way or the other? The drive is USB 2.

TIA

The reason it treated it as a new backup is that time machine treats network backups differently than locally connected ones. In general you will get significantly better performance and speed of the backups if the drive you are backing up to is locally connected and not over the network.

I would leave the drive attached to the mini and enable file sharing so the other machines can see that drive on the network. You can then just tell the other Mac's to use that drive to backup to. That's what I do in our setup and it works perfectly.

Thanks for the comments, I get the local drive performance for e Mac mini, but what about the laptops? They'll have 2 network connections for their backups: laptop -> router -> mini. Or does drive sharing do some kind of point to point?

The USB ports on the Airports are really slow so I'd bet you'd get faster backups going MacBook > router > Mini then to a USB drive off the Airport.

note, if the mini AND the laptop are connected wirelessly, it would be tremendously slow.. i'm pretty sure it will be slower than using the backup on the usb port of the AEBS

My setup is similar, in that attached to my Airport Extreme is a USB hub, with a GoFlex (3TB) attached to it. Also attached to the hub is a USB Brother Laser printer.

In terms of speed, I agree backups over the network are slower than a direct USB connection. However, the convenience of backups taking place without me remembering to plug in a drive, is worth it. And, the initial backup did took a long time, but once that completed (~2 hrs), future backups are incremental, and depending on how much has changed, take a few minutes or so.

Just a note: Before I started using the 3TB for backups on the network, I partitioned it as 2 disks: 1.5TB for backups, and 1.5TB for other storage. Both are visible in the finder under the Airport Extreme, but only the backups disk gets mounted/unmounted when TimeMachine is doing its thing.

Machines: MBP with 320GB drive (100GB free); iMac with 500GB drive (300GB free)

Summary: I love this setup, and recommend it to anyone who wants a good backup system without having to remember to do anything. My only concern, is if I ever do need to do a restore, it's take more time over the network. But I think I can live with that, if the situation arises.

Cheers

Backups using an external Hdd plugged to the AE is not actually supported by Apple ... maybe a better idea to upgrade to a Time Capsule ;-)