note that on a large file system with a large number of files, thats > VERY expensive, as rsync has to keep a list of every inode number on the > whole file system and verify each directory entry isn't pointing to an > inode its already linked. if there's a few million files, this data > structure gets HUGE in memory. > Thanks for the tip. I will keep an eye on the memory usage. For the filesystem in question with around 0.8 million files the memory usage of rsync is acceptable (around 160MB as reported by top RES column and 330 MB for VIRT).