Create one large hard drive partition from multiple smaller ones I've got a 4TB HD that I use for cloning, moving machines etc. I previously had it setup as 1tb, 1tb, 2tb. But I was only using c. 400gb, 400gb, 500gb respectively. 

I've now resized the partitions to make better use of the space but want to now make one large c 2.7tb partition out of the remaining space. But I can't seem to combine the empty spaces, is this possible? 

I've attached a screenshot for reference.
What you want to do can be done without using any third party tools. Basically you need move the last two partition to a position after the first partition. The fact that the source and destinations overlap complicates the procedure. This means you may need to move a partition twice. First to the bottom of the drive, then to a position after the first partition. For example, below is sparse bundle from which I can use to expose the necessary steps.



First, I created a new partition at the end of the drive.



Next, I restored the second partition source "MAX DL OLD TBC" to the forth partition destination "SL yosemite 2".



Next, I removed the second partition "MAX DL OLD TBC".



Next, I created a new partition about the same size as the original "MAX DL OLD TBC". The default volume label was "4 TB HD 2 1".



Next, I restored the forth partition source "MAX DL OLD TBC" to the second partition destination "4 TB HD 2 1".



Since there is enough free space, I created new partition after the second partition. This partition is about the same size as the "SL yosemite" partition.



Next, I restored the forth partition source "SL yosemite" to the third partition destination "MAX DL OLD TBC 2 1".



Finally, I removed the last two partitions.




  Note: Occasionally, the Disk Utility application would become confused and not correctly display the results after executing a particular step. Therefore, I needed to quit the and relaunch the Disk Utility application between certain steps. Also, a few times I need to unmount and remount the disk image.


El Capitan users would probably be better off using the command line to create and remove the partitions. This can be done by using the command diskutil. Also, the gpt command can be useful. The Disk Utility application can still be used to copy the partitions.