Why didn't my FCI Failover?

Introduction

In this lab, you will try to find the root cause of an unsuccessful FCI failover. The goal is to try and identify the cause of an unsuccessful FCI failover and fix the issue.

Objectives

At the end of this lab, you will be able to:

  • Understand the cause of unsuccessful FCI failover.
  • Fix the issue.

Estimated Time

45 minutes

Logon Information

Use the following credentials to login into virtual environment

  • Username: corpnet\cluadmin
  • Password: Pa$$w0rd

Before starting the training module, we recommend that you launch the labs and give them some time to stabilize. Please be aware that sometimes the AG may be in a resolving state and AG Replicas may be in a disconnected state. This is a platform issue and should stabilize after a few minutes

Environment review

Before you begin with the first exercise in the lab, let's review the lab environment.

  • In the lab, you have one Domain Controller and 3 nodes + 1 client computer.

  • AlwaysOnN1 and AlwaysOnN2 nodes are in the primary Datacenter.

  • AlwaysOnN3 is in the secondary datacenter.

  • For this lab, both the datacenters are in the same subnet.

  • Each node has Windows Server 2022 O/S installed.

  • SQL Server 2022 failover clustered named instance (SQLFCI\INST1) is installed

Back to the list of Labs

Exercise 1: Identify why SQL FCI cannot be failed over to cluster node AlwaysOnN2 and fix the issue

Successful completion of exercise will mean that you can failover the FCI to AlwaysOnN2 node and connect to it using SSMS on the client machine.

If time permits do Exercise 2.

Congratulations!

You have successfully completed this exercise. Click Next to advance to the next exercise.

Exercise 2: Identify why SQL FCI cannot be failed over to node AlwaysOnN3 and fix the issue

Successful completion of exercise will mean that you can failover the FCI to AlwaysOnN3 node and connect to it using SSMS on the client machine.

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Tasks

  1. Find the root cause using the guidelines and cheat sheet provided below.

Guidelines

  1. This is a non-guided activity and the attendees are expected to try and troubleshoot the issue on their own.

  2. You can use any resources (including the internet or your own scripts), to troubleshoot the issue.

  3. You can use the tools discussed in the first module to help troubleshoot the issue.

  4. The possible causes discussed earlier in the lesson can be used as guidance for troubleshooting.

  5. The instructor will discuss the troubleshooting steps, cause and solution in detail after this lab session.

  6. You might have to login directly on the individual nodes to troubleshoot the issue.

  7. Ask yourself the below questions:

    • Where do you start?
    • What logs will provide me additional insights?
    • What tools can I use to troubleshoot this issue?
    • Could one or more of the possible causes discussed earlier be the issue here?

Cheat Sheet

  1. Here are some tools that you use to troubleshoot the issue.

    • Failover Cluster Manager
    • SQL Server Configuration Manager
    • SQL Server Management Studio
    • Services applet

  2. Below are some logs that you may want to analyze

    • Windows Cluster Log
    • SQL Server Error Logs
    • NT Application and System Log

  3. To generate and collect the cluster logs of all nodes in the cluster:

    • Run PowerShell as administrator and run the below commands

      PowerShell
      Import-Module FailoverClusters
Get-ClusterLog

    • Default command Get-ClusterLog generates cluster.log file on ALL nodes in C:\Windows\Cluster\Reports folder.

      All messages are logged using UTC/GMT time. Sometimes it's difficult to translate UTC time to local time, especially for time-zones which has daylight saving. Luckily, cluster log can be generated in local time using parameter UseLocalTime . Here is the sample code.

      PowerShell
      Get-ClusterLog –UseLocalTime

      Another useful parameter is to copy the files to specific location. This command would generate logs and also dump on specified location. in below example, I am dumping logs from all nodes to C:\Temp folder.

      PowerShell
      Get-ClusterLog –Destination "C:\Temp"

    • To look at firewall settings, on each node you can search for firewall:

    • To select the SQL Server 2022 installation media

      • In the Lab on Demand (LOD) menu, click Machines, select the appropriate machine. Below screenshot shows AlwaysOnN1 virtual machine.
      • Click the drop-down box for DVD Drive and select the SQL Server 2022 installation media (ISO).

Congratulations!

You have successfully completed this exercise. Click Next to advance to the next lab.