I have 80 GB free space, but disk utility only shows about 14 GB available for partitioning. My understanding is that this could get fixed by defragging the disk. But MacOS has no defrag-tools and the drive is a SSD where it's considered bad to defragment.

Is there a way to create continous space without re-installing the whole system?


Do you mean to add a new partition or a container file on an existing partition? It the former you really just need to resize the existing HFS partition w/ diskutil resizeVolume which moves data from the end of the disk elsewhere so it may be shrunk:

Usage:  diskutil resizeVolume MountPoint|DiskIdentifier|DeviceNode size
        [part1Format part1Name part1Size part2Format part2Name part2Size
         part3Format part3Name part3Size ...]

Non-destructively resize a disk.  You may increase or decrease its size.

When decreasing size, you may optionally specify new partitions to create
to fill the newly-freed space.  Specify these new partitions as in the
diskutil partitionDisk command.  A size of zero will cause a grow fit-to-fill.
Ownership of the affected disk is required.

Valid sizes are floating-point numbers with a suffix of B(ytes), S(512-byte-
blocks), K(ilobytes), M(egabytes), G(igabytes), T(erabytes), P(etabytes),
or (%)percentage of the total size of the whole disk.

A size of "limits" will print the valid range for the current conditions of
the file system and room to grow up to an immovable object (next partition).

A size of "R" for the target partition will resize it to the maximum
possible; "R" cannot be used for the size of new partition triples, if any.

resizeVolume is only supported on a Journaled HFS+ file system.

You could theoretically use this to crunch the partition down to occupied space and then re-expand it thus creating a contiguous free region in the existing partition for a container file to utilize if you meant the latter.

  • Is diskutil resizeVolume the commandline equivalent of the diskutility GUI where I can drag around the size of the partition? That's my problem, for some reason it let's my only downsize by maximum of 14 GB, but Finder says there is 80 GB of free space. – F. Rakes Jan 14 '14 at 22:30

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