Press "Enter" to skip to content

Category: Availability Groups

Windows Server Failover Clustering Error Code 5054

Published 2021-04-09 by Kevin Feasel

Josh Darnell walks us through an error when setting up an Availability Group:

For setting up the environment, I was following this really in-depth guide from former Data Platform MVP and current Microsoft employee Ryan J. Adams: Build a SQL Cluster Lab Part 1

The guide is generally fantastic, and provides a lot of good insight into the non-SQL Server related aspects of setting up an Availability Group. I’d highly recommend checking it out if you’re interested in that sort of thing.

Relevant to this post, he has provided a diagram of how the different networks are configured:

If you’re very experienced with networking, you may already have some idea of what the problem is going to be. Don’t spoil it for everyone else okay?

I’ll admit I did not have an idea of what the problem was.

Comments closed

What to Do if a Database Isn’t Synchronizing

Published 2021-04-02 by Kevin Feasel

Lee Markup has some advice:

I currently manage 5 AlwaysOn Availability Groups. Two are on SQL Server 2014 and overdue for an upgrade, while three of them are on SQL Server 2017.  From time to time I have run into a couple of different situations that I needed to troubleshoot and I want to tell you where to look and what to check on in these scenarios. I can’t possibly tell you about everything that could go wrong, but I can tell you about my experience with AlwaysOn Availability Groups and let you decide if that experience helps you or not.

Click through for more.

Comments closed

Restoring a Database Formerly in an Availability Group

Published 2021-03-22 by Kevin Feasel

Jack Vamvas has a process for us:

Steps to restore a database from a backup device that was part of an Always On Availability Group, and now needs to be restored 

Recovery Scenario : Requesting an older database copy previously backed up 

Name of Always on Availability Group = MyAG1

Name of Always On Availability Group db = MyAGDB1

Note: this is a workflow – and there may be some slight variations depending your Availability Group set up 

Read on for rest of the workflow.

Comments closed

A Warning on Using Distributed Network Names

Published 2021-02-24 by Kevin Feasel

Allan Hirt has a warning for us:

DNNs are supported as of SQL Server 2019 CU2 and require Windows Server 2016 or later. I wrote more about them in my blog post Configure a WSFC in Azure with Windows Server 2019 for AGs and FCIs. Go there if you want to see what they look like and learn more.

Right now, I cannot wholeheartedly recommend the use of DNNs for listeners or FCIs if you are using Enterprise Edition. Why?

Read on to learn why.

Comments closed

Availability Groups and the Shakes

Published 2021-02-15 by Kevin Feasel

Niko Neugebauer coins a term:

Disclaimer: I am using the word shake by my own initiative and no Microsoft Documentation ever to my knowledge ever mentioned that situation. Those shakes are represented most of the time as health events to the cluster, such as the Lease Timeout resulting in a sudden attempt of Failover.
Why did I choose that word ? I don’t know. Honestly. 🙂

Read on to see it in context around hosts, CPU, and especially I/O.

Comments closed

Preparing an Availability Group for VM-Level Replication

Published 2021-02-11 by Kevin Feasel

David Klee takes us through an interesting scenario:

If you have a SQL Server Availability Group (AG) and the VMs are being replicated to a disaster recovery site (cloud or on-prem), chances are the networking topology is not the same at the second site. These replication technologies can include VM replication, SAN LUN replication, or replicating server-level backups to the second site. It is quite complex to have the same network subnet existing at both sites, so usually, the secondary site contains a different networking subnet structure. It means that the servers being brought up at the secondary site are going to receive different IP addresses.

The Availability Group architecture, especially with its dependency on the Windows Server Failover Cluster (WSFC) layer, are quite intolerant of having these IP addresses changed. The utilities performing the failover might not even be aware of the WSFC-specific components that need to be adjusted.

Click through to see what you can do.

Comments closed

Changing IP Addresses in an Availability Group

Published 2021-02-02 by Kevin Feasel

Sreekanth Bandarla is ready to make a change:

In this blog post, let’s see how to change all the IP addresses involved in a typical Always on Availability group configuration. In my setup, I have an AG with two replicas and a listener. See below to get an idea of my current environment on which I am going to change all the underlying IP addresses.

Click through for a step-by-step process, as well as a few things to remember.

Comments closed

Checking for Missing Failover Cluster Dependencies

Published 2021-02-01 by Kevin Feasel

Chad Callihan ran into an error creating a new database:

A tool that restores a model type database and does a bit of configuration work was failing. I took a look at the stores procedures and started to go step by step. It didn’t take long before getting this error message when attempting to restore/create a database:

Msg 5184, Level 16, State 2, Line 3
Cannot use file ‘D:\sql_log\CC_Test_name_4.ldf’ for clustered server. Only formatted files on which the cluster resource of the server has a dependency can be used. Either the disk resource containing the file is not present in the cluster group or the cluster resource of the Sql Server does not have a dependency on it.

Click through for the solution.

Comments closed

Sync Logins between Availability Group Replicas

Published 2020-12-21 by Kevin Feasel

Taryn Pratt has a process:

Always On Availability Groups can support up to nine availability replicas, and while we don’t use anywhere near that many replicas in each of our clusters, we do have 2 replicas per cluster (3 servers total), with the replicas being used as a readable secondary.

Since we use readable secondaries in our environments, the application needs to connect to both the primary and the secondary servers with the same login. The catch is, logins don’t automatically sync across replicas. If the logins don’t sync, the application won’t connect to a secondary, which results in login failures.

Read on for one way to solve the problem.

Comments closed

Monitoring Availability Groups via DMV

Published 2020-11-20 by Kevin Feasel

Rajendra Gupta continues a series on Availability Groups:

In the previous article, Explore dynamic management views for monitoring SQL Server Always On Availability Groups, we explored the DMV’s for the Availability group for Windows Failover Clusters.

This article takes a further step and covers useful DMV related to availability replica and databases. Let’s start our journey with this article.

Click through for the article.

Comments closed