Every few years I move all my files into a disk image and start from scratch. I need the image to be (mounted) read-only for safety and searchable.
So far I used sparseimage, made Spotlight index them and then locked the file.
This time I tried sparsebundle as it was “recommended for 10.6” and can put images on file systems that don’t support tens of gigabytes in a single file. However I can’t find a way to make them read-only, no matter what permissions I assign to the bundle or the bands folder inside.
I suggest that you use a disk image format that’s inherently read-only, rather than trying to change the file permissions. For example, you could convert your .sparsebundle to a .dmg that uses bzip2 compression. This will save disk space, protect your files with a checksum, and also ensure that they’re not modified. If the maximum file size is a concern, you could create a segmented .dmg.
Unfortunately that step breaks Spotlight. I can open the image before and after conversion side-by-side and only get (fast) filename matches for the .dmg but content matches for the sparsebundle.
Well, this is strange. I’ve verified that even if the read-only disk image contains the Spotlight index files, Spotlight still won’t search it. Does anyone know what’s going on here?
I guess you could set all the folders on your mounted sparsebundle to read-only.