rsync syncs everything everytime...?

[HAL9000]

Hey People, I've got two disks, I need to sync some of the data on the first disk onto the second disk, I've started using rsync for the first time but: It sync's everything everytime and with this data being about 2TB that's no use to me.

command: rsync -rv /disk1/source/ /disk2/.destination/

Suggestions?

 

[HAL9000]

crap that figured it out.

--size-only

 

[Soulkeeper]

I use rsync -tavxHAXS --delete --progress /mnt/sdb1/ /mnt/sdc1
the trailing slash is important