I always wanted to have my own VCS cluster LAB where I could do my RnD. Which is generally not possible in the production setup (off course !). So I decided to build this awesome home LAB with VMWare workstation on my laptop. Note : The software iSCSI software used for this setup does not support SCSI3 PGR feature which is required for configuring fencing. As this is a test LAB, we can ignore this shortcoming. The vxfentsthdw command to test the disk for SCSI3 PGR capability would fail for the … [Read more...] about VCS cluster 5.1 LAB using VMware workstation : The Setup
VCS
How to add/remove Low/High priority LLT links in VCS online
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 restarting VCS using -force option) 1. Method 1 (using lltconfig) Add/Remove High Priority LLT link To add a high priority LLT link online (without restarting LLT) : # lltconfig … [Read more...] about How to add/remove Low/High priority LLT links in VCS online
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. Install and configure VCS on the new node Install VCS cluster software to node03. When asked to configure it, select "no". After you have finished installing the vcs software run installsf from the software … [Read more...] about How to add a node to an active VCS 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 running on it. Freeze node and halt VCS Freeze the node03 and stop VCS on that node by evacuating it, so that service group SG03 will switch over to either node01 or node02. # … [Read more...] about How to remove a node from an active VCS cluster
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 using the installer script and by using command line. Before configuring the disks for fencing you can run a test to confirm whether they are SCSI3-PGR compatible disks. The vxfentsthdw script guides you … [Read more...] about How to configure VCS I/O fencing – Command line and installer utility
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 with other nodes with which it has more than one LLT link active and a Jeopardy membership with the node with which it has only one LLT link active. So as shown in the digram below node03 … [Read more...] about vcs basics – Communication faults, jeopardy, split brain, I/O fencing
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 main purpose of LLT is to transmit heartbeats. - GAB determines the state of a node with the heartbeats sent over the LLTs. - LLTs are also used to distribute the inter … [Read more...] about VCS cluster 101 – Cluster Communications, GAB, LLT, HAD
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 a shared storage at mount point /oracle/product/10.2.0 2. All Data and other files will be stored under /u01/oradata 3. 192.168.1.4 will be used as a virtual IP to … [Read more...] about VCS sample configuration – Oracle Database