OJS

Creating a test instance
Centos 7 was choosen as the operating system
The test server is to be built as a virtual machine. It's probably better not to use volume management for the root partition as it makes the task of growing disks more complex.
The vm should have a swap partition of around 5Gb, and a root partition. No other partitions are necessary.
An initial disk size of 60Gb is sufficient as expansion can be carried out when needed.
The default xfs filesystem can be used as it seems to have the ability to be expanded when the size of the virtual disk in increased.
Mariadb is used for the database as it is the variant of Mysql which is supplied with Centos 7.
Php needs installing along with the relevant php drivers for Mysql.
The following php packages resulted in a working OJS installation:

php-common-5.4.16-23.el7_0.1.x86_64
php-gd-5.4.16-23.el7_0.1.x86_64
php-mysqlnd-5.4.16-23.el7_0.1.x86_64
php-cli-5.4.16-23.el7_0.1.x86_64
php-mbstring-5.4.16-23.el7_0.1.x86_64
php-pear-1.9.4-21.el7.noarch
php-process-5.4.16-23.el7_0.1.x86_64
php-xml-5.4.16-23.el7_0.1.x86_64
php-5.4.16-23.el7_0.1.x86_64
php-pdo-5.4.16-23.el7_0.1.x86_64

I created the ojs datbase user as detailed here --> Creating users and then filled in the ojs installation form with the details.