When making a rsnapshot backup from a ext4 to a ext2 filesystem, about 90% of the files cannot be opened and produce Input/Output errors.
When the target is ext4 too, it works flawless.
Any ideas how I can fix that?
Clarification: The backup runs trough without any problem in both cases but afterwards only the ext4 backup has no errors while the ext2 one is completely useless.
Why are you trying to backup an ext4 filesystem on an ext2 one? As you have noticed, ext4 to ext4 works well: this would imply that you are using features only available to ext4 and ext2 simply cannot handle them.
Take a look at the differences between these filesystems and ask yourself: should this technically work? It's difficult for anyone here to answer that, since we can't see what filesystem you're trying to backup.
In the long run, even if you modify your source filesystem to squeeze on an ext2 one, this won't scale. You'll eventually hit some other limitation, essentially leaving you on an ext4 filesystem with ext2 constraints. Just backup to an ext4 filesystem.
