I need to make a backup on my external hard drive. I looked both at rsync and incremental tar. The problem is that I want my backup to be compressed. With rsync I can only compress the data transfer, but not the result. With tar the result is indeed compressed, but I will have a lot of incremental archives, when I want to have just one compressed file. So, I see 2 options: either I need rsync, that works with compressed target or tar, that creates just one file. Is it possible?
rsync doesn't have the capability to compress it's target. One possibility is to store your backup copy on a filesystem that supports native transparent compression (for example btrfs) which will provide you with the space saving you are looking for.