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I'm using my main office server as a "poor man's Time Capsule" with Time Machine to back up my Mac OS X boxes. It works fine but I've just built a nicer/faster/bigger server so I wanted to extend the volume that my iMac is backing up onto.

With Disk Utility, you can easily grow the sparsebundle that is providing the underlying disk image, but so far I don't seem to be able to grow the size of the Volume that is stored on said sparse bundle. For the record, the file system used is HFS+J.

Is there a way to grow the volume or am I basically stuck with recreating the Sparse Bundle and starting anew?

To clarify: I've got one sparsebundle that the iMac is backing up to via Time Machine. The sparsebundle resides on a Samba server that my Macs recognise as a backup volume via the usual well publicised hack. This sparsebundle used to be 139GB in size and I've extended the size of the bundle/image to 270GB using Disk Utility. So far, so good.

However, when I mount the image, I get the volume contained therein, which is still showing its original size of 139GB. Now it looks like Disk Utility should have been able to extend both the size of the sparsebundle and the volume stored therein, but I haven't had any success in that.

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I'm confused - I'm using Time Machine to backup my laptop to my desktop. On the desktop's time machine drive, there's a sparse bundle representing the laptop. Whenever time machine requires more space, it automatically resizes the bundle; I never have to mess around with the volume at all. – David Snyder Jul 17 '09 at 20:53
So do you want to extend the volume over two disks? – Josh Hunt Jul 18 '09 at 7:23
I've tried to clarify my question above - basically I have resized the sparsebundle to take advantage of the bigger disks in my new server, but I don't see any way of growing max size of the volume inside it. Maybe I'm missing something and it'll do it automatically, but is there a way of doing it manually? – Timo Geusch Jul 18 '09 at 19:01
up vote 1 down vote accepted

I researched this topic myself some time ago and I didn't find any solution.

One article mentioned that there were "very few programs" that can do it, without supplying any information about the mentioned programs.

Gnu parted can resize HFS+, but it can only shrink not grow. I also tried to find out if Partition Magic can grow HFS+. There is no information about that on their website. I didn't find out a support email address, they seem to only offer paid telephone support.

From all this I think there is no software that can grow HFS+.

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As you said, the problem appears to be the ability/inability of growing an HFS+ filesystem. Oh well, new image time methinks. – Timo Geusch Jul 23 '09 at 8:21
  1. Drag the disk file onto disk utility.
  2. Select the proper disk image file in the sidebar.
  3. Click the 'Resize Image' button on the toolbar.
  4. Click on the blue/grey disclosure triangle to expose the additional settings.
  5. Click on the radio button that says 'Resize Partition Only'
  6. Drag the slider all of the way to the right.

This works for the test image i created

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Thanks for the suggestion - this is basically the procedure that I followed and while I can grow the size of the sparsebundle, I con't grow the size of the HFS+ drive inside it with that method, at least not now that it's got data on it. Looks like I'll have to put this bundle aside (and keep it for future use just in case) and create a new one. – Timo Geusch Jul 23 '09 at 8:20
You can then grow the HFS+ filesystem itself by mounting the disk image, selecting the Partition tab inside Disk Utility, and extending it (by grabbing the resize corner, or entering bigger numbers.) It will confirm that it won't erase the data (if it doesn't, then /don't/ go ahead!), unmount the volume, and resize it. – jrg Jan 4 '10 at 23:29

Disk Utility can resize most partitions just fine. You can also use diskutil resizeVolume from the command line (

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