Monday, July 25, 2011

Local Backup on Lion (Mac OS X 10.7)

Local backup is a new feature in Lion. Once the time machine is setup, the local backup will be enabled. When a laptop is disconnected to the time machine drive, the local backup starts to take snapshots on the computer periodically (I still haven't figured out how often it will take).

This poses one problem. If the local drive runs low on storage, the local snapshots will take up much of the scarce space. Deleting files doesn't help -- not until the local snapshots have been pruned. One way to remove the snapshots immediately is by disabling the local snapshots. This can be done by typing the following command on the Terminal:

sudo tmutil disablelocal

Once this command has been issued, the system will start to prune the local snapshots. It may take some time (maybe a few minutes) before the disk space occupied previously by those snapshots can be recovered.