Following an Apple support article entitled: Enabling and using the “root” user in Mac OS X, and with the aid of iPartition, I was able to re-partition my User partition (located on x220’s internal 300GB drive). The use of diskutil was out of the question as I had chosen an MBR scheme during Lion’s installation.
My original partition layout (MBR) was as follows:
root# diskutil list /dev/disk0 #: TYPE NAME SIZE IDENTIFIER 0: FDisk_partition_scheme *30.0 GB disk0 1: Apple_HFS Mac OSX Lion 30.0 GB disk0s1 /dev/disk1 #: TYPE NAME SIZE IDENTIFIER 0: FDisk_partition_scheme *320.1 GB disk1 1: Apple_HFS User 260.0 GB disk1s1 2: Apple_HFS Backup 30.0 GB disk1s2
As you can see, disk1 has available unused space amounting to 30GB. I had planned to expand my User partition (/User is a symlink to /Volumes/User) to 290GB using iPartition as an administrative user, but was unable to do so as disk1 was still in use and couldn’t be mounted. Booting the system in single-user mode was not an option for me as I wanted to use iPartition’s support of non-destructive resize of HFS+.
Fortunately, I was able to enable the root account, whereby I would then kill all processes owned by my user or that had open files on disk1 - using # lsof +D /Volumes/User for the latter. iPartition would then be able to operate unimpeded.
Moving data (upon resizing) takes a while - particularly on a 300GB drive, so it is imperative to use an external power source and to disable any power saving features such as suspend.