It’s sometimes a requirement to add a new high or low priority link to the existing LLT links. This can be done online without affecting any of the cluster services. There are 2 ways to do the same online (without offlining any service group). 1. Method 1 (using lltconfig) 2. Method 2 (editing /etc/llttab and […]
Archives for October 2013
How to add a node to an active VCS cluster
There might be a requirement to add a new node to an existing VCS cluster to increase the cluster capacity. Another situation in which there is a need to add a new node is hardware upgrade of the nodes. In this post, we will be adding 3rd node (node03) to the existing 2 node cluster. […]
How to remove a node from an active VCS cluster
There might be situations when you want to remove a node from cluster. We can do this online without interrupting the cluster services. For this you should have sufficient resources to handle the load of the node which you are going to remove from the cluster. We will be removing node03 with service group SG03 […]
How to configure VCS I/O fencing – Command line and installer utility
I/O fencing is one of the very important feature of VCS and provides user the data integrity required. Let us now see how we can configure fencing in a VCS setup. This setup assumes that you already have a VCS setup up and running without fencing. Fencing can be configured in 2 ways – By […]
vcs basics – Communication faults, jeopardy, split brain, I/O fencing
Let us now see various communication faults that can occur in the VCS cluster and how VCS engine reacts to these fault. There are basically 2 types of communication failures 1. Single LLT link failure (jeopardy) When a node in the cluster has only the last LLT link intact, the node forms a regular membership […]
VCS cluster 101 – Cluster Communications, GAB, LLT, HAD
GAB, LLT and HAD forms the basic building blocks of vcs functionality. I/O fencing driver on top of it provides the required data integrity. Before diving deep into the topic lets see some basic components of VCS which contribute to the communication stack of VCS. LLT – LLT stands for low latency transport protocol. The […]
VCS sample configuration – Oracle Database
This is one of the simplest configuration of Oracle DB, under VCS. In practical scenarios you may have more mount points and multipathing configured. But once you get the basics behind configuring each resource and how to link them, its easy to configure any complex setup under VCS. Prerequisites: 1. Oracle should be installed on […]