Erase, then Copy: Disk Image Size Planning
 

So, I got a "No space left on device" message while trying to update a sparse image using a smart update "Erase, then copy". I can honestly say I'm happy about this. Because an "Erase, then failed copy" could create a big issue.

Now, I'm trying to plan for how much flex space to add to the sparseimage. What is SuperDuper! actually doing on this? Does it copy all the new stuff first and then erase? Or, does it erase after each file is successfully copied?

I much prefer the latter as I think that means I need to make my sparse image bigger than the largest file I could expect to have. The former has me adding a lot of space to disk images based of how many big files could get updated (and with a digital photographe wife, producing MANY 60 MB files in a day, that adds up to be a lot).

Thanks,

Gary

You don't have to erase-then-copy if you clear some space on the image that will allow the files to copy. The issue here is that you're likely running quite close to capacity on the source. So, when large folders of photos are moved/rearranged, you can end up with this kind of issue.

The Troubleshooting section of the User's Guide explains how Smart Update works and can help, too.