Using Rsync and SSH

Using Rsync and SSH by Try Johnson of troy.jdmz.net

I like to backup some logging, mail, and configuration information sometimes on hosts across the network and Internet, and here is a way I have found to do it. You'll need these packages installed:

* rsync

* openssh

* cron (or vixie-cron)

Please note these instructions may be specific to Red Hat Linux versions 7.3, 9, and Fedora Core 3, but I hope they won't be too hard to adapt to almost any *NIX type OS. The man pages for 'ssh' and 'rsync' should be helpful to you if you need to change some things (use the "man ssh" and "man rsync" commands).

First, I'll define some variables. In my explanation, I will be synchronizing files (copying only new or changed files) one way, and I will be starting this process from the host I want to copy things to. In other words, I will be syncing files from /remote/dir/ on remotehost, as remoteuser, to /this/dir/ on thishost, as thisuser.

I want to make sure that 'rsync' over 'ssh' works at all before I begin to automate the process, so I test it first as thisuser:

$ rsync -avz -e ssh remoteuser@remotehost:/remote/dir /this/dir/

and type in remoteuser@remotehost's password when prompted. I do need to make sure that remoteuser has read permissions to /remote/dir/ on remotehost, and that thisuser has write permissions to /this/dir/ on thishost. Also, 'rsync' and 'ssh' should be in thisuser's path (use "which ssh" and "which rsync"), 'rsync' should be in remoteuser's path, and 'sshd' should be running on remotehost.