trying to do a backup
 

I have created ssh keys and I could login with no passwd form client to server and other around,

so my question is I am trying to do backup such as /etc just for a test with rsync
and i am using this command sudo rsync -e 'ssh -x' -avz hostname:/etc /home/paxmaster/testing/backup/

but the problem is why its asking me password if i have created ssh-keys

I can login with password if i do it with regular way such as ssh ipadress

anybody could help me, it would be great thanks

When you are using sudo, you are running as root. You will need to create and exchange the key under the root account.

I have too think outside of the box, now on thx

and my other questions is how would I compare two different dir, since i did the backup i want to know if the two dir is the same, but the problem i want to compare from two different remote location, how would i do that.

thx

Well, that's rsync's job; to compare the source and destination, and send any differences.

If you want to verify that rsync is doing what you expect, you can:

ssh userid@remotehost ls -lR directory/ > remotedir.txt

and compare the file attributes against the local filesystem.