Reindl Harald wrote: > > > Am 19.01.2013 19:28, schrieb Nicolas Thierry-Mieg: >>>> no I don't think you will, since the file modification times won't have >>>> changed. >>> >>> and even if the did - who cares? >>> >>> * rsync does not transfer unchanged data ever >>> * rsync will sync the times to them from the sources >>> * so have nearly zero network traffic >> >> Not true: if you change the modification time on a file, by default >> rsync will copy the whole file again. >> >> See man rsync: >> Rsync finds files that need to be transferred using a “quick check” >> algorithm (by default) that looks for files that have changed in size or >> in last-modified time. >> >> and yes I've tested this before posting ;-) >> to avoid this you need to use --size-only > > bullshit > > yes it transfers - but with rsync algorithm > RTFM how rsync works - it will generate checksums on both > sides, tnrafser only the checksums and come to the conclusion > that the data are ident > > i am using rsync since many years for all sort of backups > and file transfers and even my thunderbird-profiles over > WAN is copied with a "virtual speed" of 200 Megabytes per second > ________________________________ > > [harry at srv-rhsoft:~]$ ls /mnt/data/profiles/thunderbird/harry/global-messages-db.sqlite > -rw-r----- 1 harry verwaltung 640M 2013-01-19 19:31 /mnt/data/profiles/thunderbird/harry/global-messages-db.sqlite > > this file will ALWAYS be changed, not only modification times > but that does not change the facht 99.8% of the file is unchanged > and rsync by design transfers only the changes over the wire > > since i am doing this DAILY between home and office machine > you do not need to explain me how rsync works and in which cases > in trafsers data - really you do not need > > i sync some TB of data daily inclduing GB large logfiles > where is also only the new part transferred all the time > woosh! chill out dude... again, read the man page. This is not true if source and dest are local: then the rsync algo is not used, and if the mod time is changed on the source the whole file will be copied. so if you're rsyncing locally, eg to a usb drive, you need --size-only as I said. Now if one of the source or dest is remote I agree with you, but this is not alwayss the case. I don't recall whether the OP expressed whether that was the case or not, though I think he mentioned wanting to backup family pictures, so it might very well be to a usb HD. Inany case I definitely know you mentioned testing things locally. Which I did, and you didn't... being wrong is ok, but you should really work on that attitude of yours.