Finally I'm at the end. These are the tings I have done before I now can start installing ownCloud on my Raspberry Pi.
The current version of ownCloud is 8.2.2 and this version would be better, cause it has full PHP7 support. But I will now install 8.1, cause there are some problems with 8.2.2 and the calendar app does not support PHP7 at the moment. But ownCloud 9 will come soon in 2016. The last time I have installed ownCloud is a while ago and so I will start with Manual Installation on Linux.Let's install the requirements MySQL, PHP and Apache2.
sudo apt-get update
sudo apt-get install mysql-server php5 apache2 libapache2-mod-php5 php5-gd php5-json php5-mysql php5-curl php5-intl php5-mcrypt php5-imagick
Now we can download ownCloud from the Download Page and extract it. Please do not forget to verify the MD5 or SHA256 sum.
wget https://download.owncloud.org/community/owncloud-8.1.5.tar.bz2
tar -xjf owncloud-8.1.5.tar.bz2
After that we will move the owncloud directory to your USB flash drive.
mv owncloud /media/gordon/sandisk/.
First we need to edit the file /etc/apache2/sites-available/000-default.conf like this.
<VirtualHost *:80>
ServerName raspberrypi
ServerAdmin webmaster@localhost
DocumentRoot /var/www/html
<Directory /var/www/html>
Options +FollowSymlinks
AllowOverride All
<IfModule mod_dav.c>
Dav off
</IfModule>
SetEnv HOME /var/www/html
SetEnv HTTP_HOME /var/www/html
</Directory>
ErrorLog ${APACHE_LOG_DIR}/error.log
CustomLog ${APACHE_LOG_DIR}/access.log combined
</VirtualHost>
Now we will link /var/www/html to /media/gordon/sandisk/owncloud and restart apache.
sudo ln -s /media/gordon/sandisk/owncloud /var/www/html
sudo service apache2 restart
After that we just have to make sure that /media/gordon/sandisk/owncloud is readable for www-data and we can visit http://raspberrypi in our browser to install ownCloud.