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Using Time Machine to backup contents of external HD

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lason

macrumors newbie
Original poster
May 14, 2007
22
0
Hi everyone,

After having an external HD fail on me and losing all of my data, I decided to get a 4TB G-Drive to use as my dedicated Time Machine drive. I have another 3TB G-Drive that I'll be using to store data to replace the failed drive. I want to use the 4TB Time Machine drive to backup the data from the 3TB drive but when I go to Time Machine preferences, that drive is greyed out and can't be included. The drive is already formated for Mac from the factory so I'm not sure why it's greyed out. Can someone help?? Thanks in advance.
 
R

RedCroissant

Suspended
Aug 13, 2011
2,268
96
lason said:
Hi everyone,

After having an external HD fail on me and losing all of my data, I decided to get a 4TB G-Drive to use as my dedicated Time Machine drive. I have another 3TB G-Drive that I'll be using to store data to replace the failed drive. I want to use the 4TB Time Machine drive to backup the data from the 3TB drive but when I go to Time Machine preferences, that drive is greyed out and can't be included. The drive is already formated for Mac from the factory so I'm not sure why it's greyed out. Can someone help?? Thanks in advance.
Click to expand...

Hello, can you take a screen shot of the info on your external HD that you want to back up? It might have to do with the permissions set for it for who can read/write to it. There should technically be no issue with TM backing up an external since I remember having to tell TM NOT to back up my externals when I had 3 connected.
 
L

lason

macrumors newbie
Original poster
May 14, 2007
22
0
2u5gms9.png
 
Last edited by a moderator:
L

lason

macrumors newbie
Original poster
May 14, 2007
22
0
The one I'm using as the backup drive isn't greyed out though
 
L

lason

macrumors newbie
Original poster
May 14, 2007
22
0
No. I renamed one of the drives and that didn't change anything.
 
L

lason

macrumors newbie
Original poster
May 14, 2007
22
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The 3TB drive was my Time Machine drive before I got the 4TB drive. I've migrated my Time Machine backups from the 3TB drive to the 4TB drive and I'm using the 3TB as a regular external HD now.
 
R

RedCroissant

Suspended
Aug 13, 2011
2,268
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lason said:
The 3TB drive was my Time Machine drive before I got the 4TB drive. I've migrated my Time Machine backups from the 3TB drive to the 4TB drive and I'm using the 3TB as a regular external HD now.
Click to expand...

How did you migrate them? The reason I ask is because doing it the wrong way will make TM think that the drive that was previously used as a TM will not be backed up to. In the TM preferences, does it show the 4TB drive as your TM drive?
 
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lason

macrumors newbie
Original poster
May 14, 2007
22
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I dragged the backup file to the new drive and it copied over, then I deleted it off the 3TB drive once it was finished.

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Time Machine does show the 4TB drive as my time capsule.
 
R

RedCroissant

Suspended
Aug 13, 2011
2,268
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lason said:
I dragged the backup file to the new drive and it copied over, then I deleted it off the 3TB drive once it was finished.

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Time Machine does show the 4TB drive as my time capsule.
Click to expand...

Well I'm sorry to say that the drag and drop, although it seems to work, is the incomplete way to do it. The proper method would have been to use disk utility to restore the information on the 3TB drive onto the 4TB drive. Because the information was dragged and dropped, TM is still recognizing your 3TB drive as a TM device and not backing it up. After all there would be no reason for a TM drive to copy itself.

What you need to do now is not simply reformat the 3TB drive, but to erase the free space, erase the drive, and then reformat again after that.
 
R

RedCroissant

Suspended
Aug 13, 2011
2,268
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lason said:
Do I do all that with Disk Utility?
Click to expand...

Yes. The reason for this is because now TM will think, even though all the files are migrated over, that there is either a new drive connected or that there was an interruption in the backup cycle. using DU "tricks" TM into thinking that nothing has changed even though you went through 2 formats an restoration cycles.
 
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lason

macrumors newbie
Original poster
May 14, 2007
22
0
Alright. I appreciate the help with this. I'm going to do the steps you recommended and I'll report back.
 
chown33

chown33

Moderator
Staff member
Aug 9, 2009
10,761
8,460
A sea of green
lason said:
The 3TB drive was my Time Machine drive before I got the 4TB drive. I've migrated my Time Machine backups from the 3TB drive to the 4TB drive and I'm using the 3TB as a regular external HD now.
Click to expand...

The grayed-out item contains nearly 3 TB of data (2.98 TB). If it's a 3 TB drive, it's nearly full.

The non-grayed-out item contains only 41.88 GB of data, which on a 3 TB drive is nearly empty. That's 0.04188 TB, or about 1.5% of total disk capacity. There may be no user-visible files, just file-system directories and related structures, taking the 41.88 GB.

According to the Get Info window, the emptier G-DRIVE is only a 3 TB drive, not 4 TB. It says "Capacity: 3 TB", and its reported "Used" size matches the 41.88 GB in the TM exclusion list.


The reason the first item is grayed-out is because it's the active Time Machine backup disk. That is, it's the disk where TM writes backups. I can tell this because TM always excludes the TM disk itself, and always shows it first in the exclusion list. A TM disk can't be backed up to itself, hence it's presence on the exclusion list.

I think you should give the new disk (presumably the emptier one) a unique name, reselect it as the TM disk, then revisit the TM exclusion list. Even if you name the disks "Newer" and "Older" it would help clarify things.
 
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lason

macrumors newbie
Original poster
May 14, 2007
22
0
Disk Utility says it'll take 12 hours just to erase the free space. This may take a while.
 
R

RedCroissant

Suspended
Aug 13, 2011
2,268
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lason said:
Disk Utility says it'll take 12 hours just to erase the free space. This may take a while.
Click to expand...

Yeah, it'll take a long time. I made that mistake the first time I tried using a new HDD for TM. Next time it'll be easier and faster.
 
ZMacintosh

ZMacintosh

macrumors 65816
Nov 13, 2008
1,445
684
lason said:
Disk Utility says it'll take 12 hours just to erase the free space. This may take a while.
Click to expand...

Why are you erasing free space?
Erasing freespace only zeros out blocks previously used by older data.

Erasing a disk in disk utility shouldnt take more then a few moments.

Just click erase or use the partition tab to format the drive
 
L

lason

macrumors newbie
Original poster
May 14, 2007
22
0
It seems like it's been stuck creating a secondary temporary file for a while and it doesn't show any estimated time left anymore.
 
L

lason

macrumors newbie
Original poster
May 14, 2007
22
0
I had to force quit disk utility because it looked like it was stuck trying to create the second temporary file. I never did have to format the drive. I was able to select it in Time Machine prefs and included it in my backups and it seems to work now.
 
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