Unison Two Ways Synchronize Ubuntu 14.04 LTS

* Install Unison Package in both server :

apt-get install unison openssh-server ssh

* Create a private/public key pair on server A :

ssh-keygen -t dsa
# Enter All

 

* Activate root :

sudo passwd root

* Copy SSH ID to the server B :

ssh-copy-id -i $HOME/.ssh/id_dsa.pub root@Ip_Address
# authorized_keys file have added to /root/.ssh/authorized_keys

* Run Unison for the first time to synchronize :

unison /var/www/ ssh://ip_address_server_B//var/www/
# Enter All if we want to copy all files and folders

* Setting Unison Script vi /root/.unison/default.prf :

# Unison preferences file
# Roots of the synchronization
root = /fileserver02/data/
root = ssh://10.10.10.8//fileserver01/data/
auto=true
batch=true
confirmbigdel=true
fastcheck=true
group=true
owner=true
prefer=newer
silent=true
times=true

* Unison Options :

man unison

* Run Unison :

unison

* Automate synchronization with cron job :

crontab -e

# Script : 
*/5 * * * * /usr/bin/unison &> /dev/null
# It would run Unison every 5 minutes.

* To find out where is the Unison type :

which unison