I have a 2 TB external USB drive partitioned into 3 "drives." Two are ~500 MB, the third ~1 GB. I have lots of spare space in the middle partition, so wanted to make it smaller and give that space to the third partition.
I was able to resize the middle partition smaller using Yosemite's Disk Utility. However, when I tried to enlarge the partition that was "last", i.e., the bottom of the partition diagram, to give it the now unallocated space, the sizing handle was at the bottom of the diagram and couldn't move down and I couldn't drag the start of the partition up in the diagram.
Can you only make a partition "longer" and not move the start or "head" of a partition? That's all I could think, but was unable to find any documentation on this. There is a box where you can enter a size value for the partition, but I was too chicken to try it without asking here first.
Thanks.
Best Answer
In Disk Utility a 2 TB disk with three partitions (2x500 GB & 1x1 TB) looks like this:
In Terminal and using
gpt
you will get the following output:The partition with the index number 2 is Volume1, index number 3 is Volume2 and finally index number 4 is Volume3. The 262144-block areas of unallocated disk space are standard Apple partitioning policy.
After resizing the second partition to 250 GB Disk Utility shows the following:
and
gpt ...
Expanding the fourth partition (Volume3) would require to move its first block (1954058936) to lower block numbers e.g. block 1465777680.
This can't be done with on-board tools like Disk Utility or command line tools like diskutil. 3rd party tools like iPartition or Stellar Partition Manager are capable of doing this though.