Introduction
One of the cool things about working in higher education is that in certain cases there is infrastructure in place that you could only dream of in other industries. In this case, I’m referring to having multiple datacenters on campus with lots of single mode fiber run between them. This makes it easy to have a stretched SAN fabric as well as private networks for cluster heartbeats.
Extended Distance Cluster
With SAN storage available in both datacenters, it makes sense to deploy an extended distance cluster for mission critical systems. Oracle VM doesn’t support an extended distance cluster per Doc ID 1602029.1. That said, Oracle RAC does support this scenario. There is documentation here for setting up an Oracle RAC extended distance cluster.
But what if I wanted to have a setup like this for other applications? If you have Oracle Hardware under Premier Support or certain Oracle Linux subscriptions, then you have the right to use Oracle Clusterware to protect applications running on Oracle Linux. You also have the right to use Oracle ACFS. Additionally, if you have a MySQL Enterprise subscription, then you have the right to use (see page 49) the MySQL Agent for Oracle Clusterware. One thing to note is that together Oracle ASM and Oracle Clusterware are called Oracle Grid Infrastructure. This is the software that makes Oracle RAC possible, so it should be possible to cluster any software in a similar manner. However, I am not a lawyer so you should confirm that you do have the right to use any of the software I have mentioned.
If you follow the instructions for a Extended Distance Cluster I am assuming:
- You have two separate Oracle VM clusters in two separate datacenters.
- You have a SAN in both datacenters and can present LUNs from them to both Oracle VM clusters.
- You have networking in place to have a private cluster network between the datacenters.
- You have a third site to use as a witness – could just be AWS.
“Regular” Cluster
You could also deploy a “regular” HA cluster with some slight modifications to these instructions. I’ll try to point out the differences along the way. The process will actually be much simpler if you are not trying to deploy and extended distance cluster.
Getting Started
The easiest way I have found to get started is to use the Oracle VM Templates for Oracle Database. During deployment, you can just deploy an empty Grid Infrastructure cluster instead of a full RAC cluster. You can just delete the Oracle Database home after deployment. You don’t have to install or configure the Grid Infrastructure software yourself – you just fill in an answer file.
You can deploy the template as is, or you can tweak the template before deployment. The template lags behind a little from the current quarterly updates. You can install patches yourself into a new template,on a deployed VM before building the cluster, or after deploying the cluster. See the FAQ of the template notes for details on that process. For our purposes, you’ll want to at least install patch 19373893 at some point. This makes it so you can soft mount your NFS share from the witness site – more on that later. You can even mix and match disks between template versions. I took the 12.1.0.2.160719 template and used just the software disk. I used the system disk from the 11.2.0.4.160719 template because I wanted Oracle Linux 6 instead of 7.