As promised in one of my previous posts about dual-primary DRBD and OCFS2, I’ve compiled a step-by-step guide for Fedora. These instructions should be somewhat close to what you would use on CentOS or Red Hat Enterprise Linux. However, CentOS and Red Hat don’t provide some of the packages needed, so you will need to use other software repositories like RPMFusion or EPEL. In this guide, I’ll be using two Fedora 14 instances in the Rackspace Cloud with separate public and private networks.
Typical configuration for a proxy-type load balancer A typical load balancing configuration using hardware devices or software implementations will be organized such that they resemble the diagram at the right. I usually call this a proxy-type load balancing solution since the load balancer proxies your request to some other nodes. The standard order of operations looks like this: client makes a request load balancer receives the request load balancer sends request to a web node the web server sends content back to the load balancer the load balancer responds to the client If you’re not familiar with load balancing, here’s an analogy.
NOTE:This post is out of date and is relevant only for GlusterFS 2.x. *High availability is certainly not a new concept, but if there’s one thing that frustrates me with high availability VM setups, it’s storage. If you don’t mind going active-passive, you can set up DRBD, toss your favorite filesystem on it, and you’re all set.If you want to go active-active, or if you want multiple nodes active at the same time, you need to use a clustered filesystem like GFS2, OCFS2 or Lustre.