OpenClinica Enterprise is available either via a cloud hosted solution or a self hosted and managed system. The base supported platform for self hosted customers is Red Hat Enterprise Linux (RHEL) 6.5 or above. RHEL is a commercially supported operating system and recommended for enterprise customers. CentOS is a free rebuild for RHEL without commercial support and is available at http://centos.org. For either, we highly recommend using the 64-bit version for best performance if your hardware is capable of supporting that architecture.

RHEL 6.x installation guide is available at https://access.redhat.com/site/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/Installation_Guide/. Using Kickstart is recommended if you prefer to automate the installation steps. However,unless you are running a large number of deployments, the interactive installer is easier to perform.

If you choose to use RHEL, we recommend selecting the “minimal” option in the package selection. Refer to https://access.redhat.com/site/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/Installation_Guide/s1-pkgselection-x86.html for more details. As noted in the installation guide, choosing this option maximizes security and performance since it reduces the number of services running and the number of updates required for maintaining the system. If you are using CentOS, the exact same options are available there as well. The net installation method allows you to download a small image and pull in packages on demand. Since an OpenClinica installation only requires a small number of packages within the operating system, this can be far more efficient than downloading the complete image. For CentOS, refer to http://www.if-not-true-then-false.com/2011/centos-6-netinstall-network-installation/ for a detailed guide on doing a net installation.

As an alternative in CentOS, you can download the minimal installation image at http://wiki.centos.org/Manuals/ReleaseNotes/CentOSMinimalCD6.0. If you choose to download the minimal image,  please note that the following core packages must be installed on the system for the OpenClinica installation and maintenance.
     *  tar
     *  unzip
     *  vim-enhanced
     *  cronie