I am using rsync 3.0.2 on a Solaris x86 platform to sync about 700GB of content to an external USB HDD. Both source and destination filesystems are ZFS so the ZFS metadata holds checksums to validate the on disk data. I will occasionally run sync in dryrun mode with checksum's and when I do I will get files reported to copy that haven't changed. Recently, of 3 files reported, using a manual MD5 hash calculation, 1 file on the ext HDD reported a different checksum (which I recopied), and 2 files had matching MD5 hash's. Of the 2 files that did not have to be recopied, a rerun of rsync did not produce the same result. The occurrence of the false negative typically happen's on larger files, and after a new population of the ext HDD. I would assume the same byte stream should produce the same result repetitively. Since the ZFS metadata doesn't indicate corruption at the disk level, I am a little confused as to what could be causing the mismatch's. Any comments? -- Darren