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@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.