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OneZweiThree

macrumors regular
Original poster
Feb 17, 2013
224
329
Bavaria
Hey people,

Im currently trying to re-partition my external HDD.
Here is my current Setup:

Partition A: 200GB (0 used)
Partition B: 700GB ( 250 used)
Partition C: 100GB (0 used)

What i want to have:

Partition A: 500GB
Partition B: 500GB (without loosing the 250GB already used)

Is this possibly at all, without using another HDD?
Because currently, if i choose the external HDD in the Disk Utility, the partition button is greyed out and i cant click it.

Thanks for your help!
 

daflake

macrumors 6502a
Apr 8, 2008
920
4,329
I would take a look at GParted (Google it) to see if it can do what you want. Is the external drive HFS+?
 

daflake

macrumors 6502a
Apr 8, 2008
920
4,329
I have actually no idea. It says macOS Extended (Journaled) on each partition, if thats what you are looking for?!


Yep, but a little research just showed that GParted can't grow a partition of this nature.

https://en.wikipedia.org/wiki/GParted

What I would do is delete A and C (not being used) then shrink your B partition by 200. Then you could create a new partition of 500 and get what you are looking for. I still think you might need a 3rd party tool. Maybe someone else can chime in with some assistance as I have been off of Mac for a while now. What I suggested could easily be done in Windows and Linux.
 

KALLT

macrumors 603
Sep 23, 2008
5,361
3,378
Partitions can only grow or shrink at the top. In your case, you cannot get around deleting partitions.

I suggest you resize partition B so that A and B have a combined size of 500 GB (you might be able to do this also by splitting partition B into B1 and B2, where your data resides on B1). Then you simply delete partition C (and B2), clone partition B (or B1) to partition C, then delete partitions A and B to create a new partition.

This can be done with Disk Utility.

Because currently, if i choose the external HDD in the Disk Utility, the partition button is greyed out and i cant click it.

You have to select the drive, not a partition. Only a drive can be partitioned.
 

OneZweiThree

macrumors regular
Original poster
Feb 17, 2013
224
329
Bavaria
Yep, but a little research just showed that GParted can't grow a partition of this nature.

https://en.wikipedia.org/wiki/GParted

What I would do is delete A and C (not being used) then shrink your B partition by 200. Then you could create a new partition of 500 and get what you are looking for. I still think you might need a 3rd party tool. Maybe someone else can chime in with some assistance as I have been off of Mac for a while now. What I suggested could easily be done in Windows and Linux.

Thanks for your help. If it doesnt work on macOS, i can probably ask a friend, who uses Linux, to help me out.
[doublepost=1483624517][/doublepost]
Partitions can only grow or shrink towards the top. In your case, you cannot get around deleting partitions.

I suggest you resize partition B so that A and B have a combined size of 500 GB (you might be able to do this also by splitting the partition into B1 and B2, where your data resides on B1. Then you simply delete partition C (and B2), clone partition B (or B1) to partition C, then delete partitions A and B to create a new partition.

This can be done with Disk Utility.



You have to select the drive, not a partition. Only a drive can be partitioned.

But even when i select the drive, the "partition" button stays greyed out. Do I need to do something else, before I can partition the drive?
 

KALLT

macrumors 603
Sep 23, 2008
5,361
3,378
Are all the disks mounted and unlocked?

You can give us an overview of your setup with this Terminal command:
Code:
diskutil list
 

OneZweiThree

macrumors regular
Original poster
Feb 17, 2013
224
329
Bavaria
Are all the disks mounted and unlocked?

You can give us an overview of your setup with this Terminal command:
Code:
diskutil list

here is a screenshot from the terminal:


http://imgur.com/a/1ftrJ

When i hover over the greyed out partition button, it says something like "master Boot record-drives can not be partitioned". (its in german for me, so i dont know the exact english wording)
I guess, this is the problem then, right?
 

KALLT

macrumors 603
Sep 23, 2008
5,361
3,378
Master Boot Record is indeed supported only to a limited extent in Disk Utility. I think you may be able to achieve what you want with several Unix tools, particularly the fdisk command, but I have very little experience with that one and it is a pain to use. The best way would be to transfer the data to another drive and then set up the drive from scratch.

Alternatively, a Linux system can indeed use GParted to help you out.
 

Fishrrman

macrumors Penryn
Feb 20, 2009
28,457
12,573
OP:

If you really want to do this cleanly and reliably, there's one way that's guaranteed:

1. Back up partition B to another drive (I recommend CarbonCopyCloner or SuperDuper)
2. Re-initialize the drive
3. Re-partition it as desired
4. Use CCC (or SD) to "clone back" from the second drive to the first one.

A little more work, but not really that much.
This will work, 100%.
 

FreakinEurekan

macrumors 603
Sep 8, 2011
5,658
2,724
Hey people,

Im currently trying to re-partition my external HDD.
Here is my current Setup:

Partition A: 200GB (0 used)
Partition B: 700GB ( 250 used)
Partition C: 100GB (0 used)

What i want to have:

Partition A: 500GB
Partition B: 500GB (without loosing the 250GB already used)

Is this possibly at all, without using another HDD?
Because currently, if i choose the external HDD in the Disk Utility, the partition button is greyed out and i cant click it.

Thanks for your help!
Reminds me of one of those pegs-and-rings puzzles.

Delete C, resize B to 300GB. Create new C of 500GB, copy data from B to C. Delete B, resize A to take up the empty space.
 

OneZweiThree

macrumors regular
Original poster
Feb 17, 2013
224
329
Bavaria
OP:

If you really want to do this cleanly and reliably, there's one way that's guaranteed:

1. Back up partition B to another drive (I recommend CarbonCopyCloner or SuperDuper)
2. Re-initialize the drive
3. Re-partition it as desired
4. Use CCC (or SD) to "clone back" from the second drive to the first one.

A little more work, but not really that much.
This will work, 100%.

Thanks for your help. I borrowed a second HDD from a friend and did it exactly that way. Worked perfectly.
 
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