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ujjain
Asked: 2011-06-13 05:20:45 +0800 CST

Why does rsync have to be installed on both sides to work?

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This might be a silly question, but I wanted to keep some of my servers clean and prefer not to install any additional software.

But I always thought rsync would copy data over SSH and would not need rsync on the remote end?

/usr/bin/rsync -a --delete --numeric-ids --relative --delete-excluded     --rsh=/usr/bin/ssh root@server01:/etc /.snapshot/hourly.0/server01
rsync: command not found
ssh rsync

1 Answers

  1. Best Answer

    rsync works by doing quick calculations at both ends looking at the timestamps and existence of all the found files in a particular location. Once it does this, it communicates back to the origin rsync about the found list and the origin can then use that information to decide what files it needs to send. That way only the recently modified or new files get transmitted to the other side. The rsync binary on the remote side is responsible for getting the list together of what already exists and then receiving each of the files that need to be transmitted and putting them in place.

    You should note that rsync works over more than just SSH. SSH is the default, but other forms of remote login (like insecure rlogin) will work as well.

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