I never believed it before, but today I experienced its suckiness for myself. iDisk sucks for big files, especially disk images.
So, today I thought I would back up some important files on an encrypted disk image on my MobileMe’s iDisk. What a big mistake that turned out to be. I had copied that 550 MB disc image to iDisk a while ago. At the time it took 2 hours to copy at my current internet line’s upload speed. I had expected that, so fine.
I tried to see what happens when I mount that disc image directly from iDisk. First, in order to mount, it took nearly 20 minutes. Fine.
Then, I copied some files (about 90 MB worth) to the mounted image. Naïvely, I thought it would take the time needed to transfer 90 MB at the speed of 1 Mbit/s. But NOOO, it seemed to have copied the files to a local copy of the disc image and then proceeded to transfer the whole disk image back to MobileMe.
When I realized what it’s doing, I clicked the Finder’s x button in the copy progress bar to cancel the operation. Well, it seemed to have changed the local copy to cancel the copy operation, and then it seemed to proceed to transfer the whole disk image to MobileMe AGAIN. So I left the house to give it some time to finish without getting too frustrated as my Mac became unusable during the transfer. I couldn’t open a file using the Open file dialog box and worse, I couldn’t save a new file. The Save dialog box was waiting for all the disks to be ready and the iDisk wouldn’t be ready before the transfer was complete.
I came back to find the transfer complete and my MacPro usable again.
But, but… wait! That’s not all.
When I clicked the eject button to eject the disk image and then to eject the iDisk, for some unexplainable reason, it seemed to transfer the disk image over AGAIN.
As I write this rant, the disk image and iDisk icon are both dimmed and my network monitor shows a transfer taking place at the full speed. It’s been going on for the last hour and I expect it to last another hour. I don’t want to kill the process so that I don’t corrupt the remote copy of the big file.
Well, I learned my lesson and I would never use iDisk in this manner ever again. I may back up small files, but never big ones. iDisk sucks.