I love my MacBook, but we’re constantly in a battle for resources, often hard drive space. Last night that free space had dwindled to a mere 400MB, prompting the ever popular warning that my startup disk was almost full. But where to reclaim the space? Firing up the indispensable GrandPerspective, I found one significant culprit: my iDisk’s local image was eating up a belly-bursting 8.55GB. Back when Apple raised iDisk storage to 10GB, I thought I was being clever by upping my mail storage to 5GB, leaving the other 5GB for my iDisk, since I really only store documents on it. Double checking my .Mac account showed that allocation was still accurate. So why, in the name of Jobs, if I only had 5GB of space allocated to my iDisk and was only using less than 2GB of that, was the image taking up almost 9 gigabytes?
I complained as much to Derik, who offered me this suggestion: turn off iDisk syncing, then turn it on again, and see if that forces it to create a new image. So a quick trip to the .Mac preference pane later and lo and behold, I jump to 9GB available. A couple of other deleted files later, and I’m up to 11GB free right now.
So if you’re running a little low on disk space and you’ve got iDisk syncing on, you might give this trick a shot.
I noticed that I hadn't pruned that disk image from my backup set when my incrementals made a huge jump in size (forcing me to delete more of my old backups than I'd like). Something else to watch out for, since I'm sure everyone reading (and writing) this block performs regular backups.
I believe the local iDisk image is a sparse disk image. There images can dynamically expand as more space is needed, but they cannot dynamically shrink unused space. Turning the syncing on/off creates a new image and there are manual ways to compress the image. In fact, I recall reading about them in MacUser...