Load balancing and clustering

Load balancing and clustering Open-Xchange

General

Open-Xchange Server 6 is primary built for the Software-as-a-Service world. Hosting and telecommunication providers around the world use Open-Xchange to offer hosted services to their customers. Open-Xchange Server 6 scales vertical and horizontal which means either use a more powerful server or add more machines to fulfill resource requirements. While upgrading a single server installation inevitable gets to a point where costs rise faster than performance gains, adding some simple machines to the installation provides linear cost increase and a slightly more complex administration. Besides the fiscal impact of using medium sized servers another key argument for clustering is service availability, single nodes can go down for maintenance without influencing the general service availability. A typical scenario for clustering is virtualization where multiple nodes can provide resources on demand.

One of the main principles of Open-Xchange Server 6 is the ability to utilize several medium sized servers. This guide will outline the basic principles of clustering Open-Xchange Server instances and provide load balancing to utilize all nodes of a cluster.

Requirements

Since clustering and load balancing is an advanced topic, skills on operating system and Open-Xchange Server 6 administration are required. To gain those skills, please refer to the documentation repository and general system administration lecture. With this guide we're going to set up five machines in total. Therefor it's recommended to get some training on a virtualized environment first. When rolling out the setup it is recommended to use real hardware or enterprise grade virtualization solutions like VMware ESX or Citrix XEN. These types servers will be set up:

• 1 Webserver (Apache)
• 2 Groupware nodes (Open-Xchange Server 6)
• 2 Database servers (MySQL Master/Slave)

To maintain consistency throughout the guide, each system gets a unique name which can be set as hostname. The IP addresses are also used through the whole guide but they may differ at the actual network setup. All systems run Debian GNU/Linux 5.0 (Lenny), any other supported platform works as well. All assumptions and instructions about system configuration is based on a minimal installation of the operating system. This guide is valid for Open-Xchange 6.10.

• web (10.20.30.210)
• oxgw01 (10.20.30.213)
• oxgw02 (10.20.30.215)
• sqlmaster (10.20.30.217)
• sqlslave (10.20.30.219)

When finishing the guide the setup will provide several load balancing and clustering features.

• Session load balancing
• Open-Xchange clustering
• Database master/slave replication
• Database read/write separation
• Distributed file storage
• Remote logging