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 […]
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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 […]
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 […]