Category: Clustering

Kellyn Gorman continues a series on Oracle Real Application Clusters:

Furthering on our Oracle Real Application Clusters (RAC) knowledge, we’re going to go deeper into what we watch for a RAC database that may be different than a single instance.  RAC is built for scale and instance resilience, distributing workloads across multiple nodes.  At the same time, what gives it strength introduces monitoring complexity, especially when you’re not just watching a single instance but multiple, interconnected ones. To manage performance effectively in RAC, you need to understand the difference between V$ and GV$ views, what they show you, and how to interpret cluster-level wait events.  Along with performance, the overall health of the RAC cluster and interconnect must be known, too.

Click through for Kellyn’s explanation.

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Kellyn Gorman continues a series:

After my last blog post on Oracle Real Application Clusters (RAC) I was asked to talk about both health and how performance impact can affect a RAC database. Its architecture enables failover, workload distribution, and offers an option to scale performance, but only when all nodes play well together. When one node drags behind or becomes unstable, RAC has no choice but to protect the rest of the cluster- so help me, Oracle Gods. This protection can come in the form of node eviction, which can be both disruptive and at times avoidable with proactive monitoring and intervention.

Click through to learn how Oracle monitors node health, the types of issues you might run into, and how to prevent node eviction.

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Kellyn Gorman gives us a primer:

Oracle Real Application Clusters (RAC) is still one of the most robust instance high-availability and scalability solutions, designed to provide resilience, performance, and continuous service for many Oracle enterprise workloads. Whether deployed on two nodes or a complex multi-node setup, RAC ensures your database infrastructure is both fault-tolerant and responsive under increasing demand.  RAC is an essential part of the Maximum Availability Architecture (MAA) recommended practices, (and in my experience) found in about 40% of small to medium Oracle environments, 98% of large enterprise environments and 100% of Exadata engineered systems. 

In this post, we’ll walk through the architectural foundation of RAC, configuration essentials, and a real-world transactional scenario that highlights the importance of its shared and synchronized architecture.

Read on to learn more.

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Salman Ahmed builds a cluster:

pg_cirrus is a simple and automated solution to deploy highly available 3-node PostgreSQL clusters with auto failover. It is built using Ansible and to perform auto failover and load balancing we are using pgpool.

We understand that setting up 3-node HA cluster using pg_cirrus on cloud environment isn’t as simple as setting it up on VMs. In this blog we will guide you in setting up a 3-node HA cluster using pg_cirrus on AWS EC2 instances.

Read on for the step-by-step instructions.

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Jonathan Kehayias troubleshoots a Windows Server clustering problem:

While working on a video recording for Paul this week I ran into an interesting problem with one of my Windows Server 2016 clusters. While attempting to add a new node to the cluster I ran into an exception calling Add-ClusterNode:

The server ‘SQL2K16-AG03.SQLskillsDemos.com’ could not be added to the cluster.
An error occurred while adding node ‘SQL2K16-AG03.SQLskillsDemos.com’ to cluster ‘SQL2K16-WSFC’.

Keyset does not exist

The windows account I was using was the domain administrator account and I had just recently made modifications that involved the certificate store on this specific VM, so I decided to take a backup of the VMDK and then revert to a snapshot to try again, and this time it worked.  So needless to say I was intrigued as to what I could have done that would be causing this error to happen.

Read on to see what the root cause was and how you can fix it.

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