SQL Server clustering is one of the oldest and most used techniques when it comes to developing a highly available configuration. Though this has been used by many for years, there are nuances that comes up once in a while if you are a junior DBA that you would like to validate your understanding. In one such mails that landed to my Inbox asked what are the significance of the various rules we validate when configuring a cluster. The mail was for SQL Server 2008 edition but this seemed simple yet no one seemed to have written about it.
On this Landing page of the Cluster Global Rules in SQL Server, this is a set of 11 Rules. We only run validation on the node we are doing the setup on. Just as we can understand, some of the rules are critical rules and others are merely optional rules. I am outlining based on what I received from my reader as questions:
- Fusion Active Template Library (ATL): Checks if a computer restart is required because of broken fusion ATL. A pending restart can cause SQL Server Setup to fail.
- Unsupported SQL Server Products: Checks whether SQL Server 7.0 or SQL Server 7.0 OLAP Services is installed. SQL Server 2008 is not supported with SQL Server 7.0.
- Not Clustered or the cluster service is up and online: Verifies that the computer is not clustered or that the computer is clustered and the cluster service is online.
- Windows Management Instrumentation (WMI) Services (“Node Name”) – Local Node: Checks whether the WMI service is running on the cluster because Setup is dependent on this service.
- Cluster Remote Access (“Node Name”) – Local Node: Checks whether the user running this Setup operation has remote access on the remote cluster node(s).
- Remote registry service (“Node Name”) – Remote Node: Checks whether the Remote Registry service is enabled.
- Domain Controller: Checks if the computer is a Windows Domain controller.
- Microsoft .NET Application Security: Verifies that the computer is connected to the Internet. When a Microsoft .NET application like Microsoft Management Studio starts, there may be a slight delay while the .NET security check validates a certificate.
- Network binding order: Checks to see if the computer domain server is on the network that is bound to the top of the network order.
- Windows Firewall: Checks whether the Windows Firewall is enabled.
- DNS settings (“Node Name”) – Local Node: Checks if the DNS search list on computer (“Node Name”) is consistent with the other nodes of a cluster.
I am sure, the number of checks might get expanded or shrunk based on the version of SQL Server we are working on. I am glad I could demystify some of the basics to junior DBA who posted this question to me. I am curious to understand to how many actually look though the list of rules ever? Do you know what were the various rules that were run on the setup? Let me know your thoughts.
Reference : Pinal Dave (https://blog.sqlauthority.com)
