Backup the configuration and data first
Check current release
#sudo cat /etc/*release PRETTY_NAME="Debian GNU/Linux 7 (wheezy)" NAME="Debian GNU/Linux" VERSION_ID="7" VERSION="7 (wheezy)" ID=debian ANSI_COLOR="1;31" HOME_URL="http://www.debian.org/" SUPPORT_URL="http://www.debian.org/support/" BUG_REPORT_URL="http://bugs.debian.org/"
Configuration files in the /etc directory
#tar -pczf etc.tar.gz --absolute-names /etc
Backup of the /var/www website directory.
#tar -pczf www.tar.gz --absolute-names /var/www
Backup of the /home directories.
#tar -pczf home.tar.gz --absolute-names /home
For ISPConfig 3 users: Backup of your email server files.
#tar -pczf vmail.tar.gz --absolute-names /var/vmail
Backup MySQL databases
#mysqldump --defaults-file=/etc/mysql/debian.cnf -cCeQ --hex-blob --quote-names --routines --events --triggers --all-databases -r all_databases.sql
Then move the tar.gz and .sql files for safe storage on a backup drive.
Check the apt sources.list file
Before upgrade to Jessie, all available Wheezy must updates first. On some systems the package source is defined as “stable” in the sources.list file instead of “wheezy” or “jessie”. To avoid an accidental early upgrade to Jessie, please check the sources.list now and ensure that it contains “wheezy” and not “stable” as source:
#nano /etc/apt/sources.list deb http://ftp.us.debian.org/debian wheezy main contrib non-free deb-src http://ftp.us.debian.org/debian wheezy main contrib non-free deb http://ftp.us.debian.org/debian wheezy-updates main contrib non-free deb http://ftp.us.debian.org/debian-security wheezy/updates main contrib non-free
#apt-get update -y && apt-get upgrade -y && apt-get dist-upgrade -y
Update the sources.list for Jessie
Edit the /etc/apt/sources.list file again:
#nano /etc/apt/sources.list
and replace its content with the following lines:
deb http://ftp.us.debian.org/debian/ jessie main contrib non-free deb-src http://ftp.us.debian.org/debian/ jessie main contrib non-free deb http://httpredir.debian.org/debian jessie-updates main contrib non-free deb-src http://httpredir.debian.org/debian jessie-updates main contrib non-free deb http://security.debian.org/ jessie/updates main contrib non-free deb-src http://security.debian.org/ jessie/updates main contrib non-free
apt-get update -y && apt-get upgrade -y && apt-get dist-upgrade -y
reboot
To check which Debian version is currently installed on the system, take a look at the file /etc/os-release.
#cat /etc/os-release #lsb_release -a
Extract all the tar.gz files to the folder (/var/www/html, /etc/)
#tar -xvf www.tar.gz
Move all folder and files
#mv /sourcefolder/{,.[^.]}* /destinationfolder/