Backup of an external drive ???

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Level 1

27 points

Backup of an external drive ???

Hello

I have disk drive connected to an Airport extreme for backups using Time Machine. Working well.

I'm considering purchasing another drive that I would like to connect to my Macbook Pro to extend it's disk space (320G internal drive + 500G external drive connented via USB or Firewire to my MacBook Pro).

Can Time Machine be setup to backup both my internal and an external drive to the backup drive?

MacBook Pro, Mac OS X (10.5.6)

Posted on Feb 17, 2009 3:18 PM

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Answer 1

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VA2020

Level 4

3,455 points

Feb 17, 2009 3:50 PM in response to tictac2929

Time Machine can be set up to backup the MacBook and any +locally attached+ HDDs formatted HFS+. However, based on the capacity of those drives, your TM backup drive would need to be quite larger. Unfortunately, you cannot span TM backups over more than one disk (Drobo, maybe?).

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Answer 2

tictac2929 Author

Level 1

27 points

Feb 17, 2009 4:01 PM in response to VA2020

OK cool.

I assume that I can use the Mac to format the external drive in HFS?

Now....
- lets assume the external disk was attached and that the initial backup was done successfully (this backup takes longer since it will backup everything on that disk)
- then let say the disk is removed and that during that time, TM goes through another backup cycle
- then let say the disk is connected again... will TM do an initial backup again on this disk or will it backup only additional content?

Hope I'm clear...

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Answer 3

Pondini

Level 8

38,863 points

Feb 17, 2009 6:41 PM in response to tictac2929

yvonarchambault wrote:
- lets assume the external disk was attached and that the initial backup was done successfully (this backup takes longer since it will backup everything on that disk)
- then let say the disk is removed and that during that time, TM goes through another backup cycle
- then let say the disk is connected again... will TM do an initial backup again on this disk or will it backup only additional content?

Usually, it will only back-up the changes. (Each disk/partition is tracked and evaluated separately.) But if several days elapse between backups, it may back the whole disk up again.

This is undocumented -- several people think it's about 10 days, others think it's some combination of how many days and how much has changed. But I've not seen any reports of it happening in under a week.

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