Dear tar-experts: I have learned that changing the kernel to not modify ctime when just the nlink-value has changed in an inode was a nice idea but has some unwanted side-effects.
Also it's too hard for me to implement. Whenever a changed inode is written to disk, its ctime value will be set to current time. At that point the kernel does not know what part of the inode has changed. There's no easy way to distinguish "real" changes (i.e. permission, mtime, acl) from "technical" changes (st_nlink-changes only). So I have to change our backup-strategy which now does a lot of hard-linking, due to resync -aHAx --link-dest=lastbackup src/ newbackup This saves a lot of space since unmodified files in lastbackup will be hardlinked into newbackup but it will change the ctime value of all unmodified files in both lastbackup and newbackup. So my final conclusion is: rsync aint no backup tool! Thank you all for your helpfull comments. Peter
