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Category: HA / DR

Business Continuity Options in Azure

Published 2025-11-10 by Kevin Feasel

Aleksey Vitsko enumerates available options:

You may be familiar with high availability (HA) and disaster recovery (DR) features that are available in SQL Server and have experience configuring and managing them. But you have ever heard of or tried Azure high availability or Azure disaster recovery features. How can I learn more about what Azure brings in terms of HA and DR for Azure SQL offerings – including SQL VMs?

Read on for a variety of options depending upon whether you’re using SQL Server on a VM, Azure SQL Database, or Azure SQL Managed Instance.

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Windows Clustering for the DBA

Published 2025-11-06 by Kevin Feasel

Sandra Delany is perilously close to running afoul of Betteridge’s Law of Headlines:

Should a SQL Server DBA know how a Windows cluster works, and or how to create a Windows cluster, or troubleshoot a cluster? Or should we, as DBAs, stay in our lane? In some organizations, a line is drawn between what a DBA can and can’t do and the System Administrator (SA) has the Infrastructure roles and responsibilities. This is fine, but that doesn’t mean a DBA shouldn’t know how to troubleshoot a FCI (Failover Cluster Instance) or AG (Availability Group) issue after an unplanned cluster-level failover.  (Yes – you can create an AG without a cluster, but that will not be taken into consideration here.)

Read on for some quick tips to get ramped up on what is available in a Failover Cluster Instance.

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Business Continuity in PostgreSQL

Published 2025-10-15 by Kevin Feasel

Warda Bibi lays out the basics of high availability and disaster recovery in PostgreSQL:

System outages, hardware failures, or accidental data loss can strike without warning. What determines whether operations resume smoothly or grind to a halt is the strength of the disaster recovery setup. PostgreSQL is built with powerful features that make reliable recovery possible.

This post takes a closer look at how these components work together behind the scenes to protect data integrity, enable consistent restores, and ensure your database can recover from any failure scenario.

This is mostly an architecture-level view, but then again, a lot of HA/DR is about making good architectural decisions.

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The Basics of Log Shipping

Published 2025-08-28 by Kevin Feasel

Kevin Hill explains why log shipping is still a viable disaster recovery approach, 25 years later:

In a world where shiny new HA/DR features get all the press, there’s one SQL Server technology that just keeps doing its job.

Log Shipping has been around since SQL Server 2000. It doesn’t make headlines, it doesn’t have fancy dashboards, and it’s not going to win you any architecture awards. But for the right environment and use case, it’s rock solid and can save your bacon job in a disaster.

Read on for a briefing on the topic.

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Building 9’s with PostgreSQL High Availability Features

Published 2025-08-11 by Kevin Feasel

Semab Tariq explains some of our options:

When you are running mission-critical applications, like online banking, healthcare systems, or global e-commerce platforms, every second of downtime can cost millions and damage your business reputation. That’s why many customers aim for four-nines (99.99%) or five-nines (99.999%) availability for their applications

In this post, we will walk through what those nines really mean and, more importantly, which PostgreSQL cluster setup will get you there.

Read on to see what you can do to get to each 9, as well as some unexpected risks to keep in mind along the way. And, of course, each rung up move up the ladder will generally cost you more money and administrative effort.

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Tips for Highly Available PostgreSQL Systems

Published 2025-07-22 by Kevin Feasel

Semab Tariq provides some high-level guidance:

In today’s digital landscape, downtime isn’t just inconvenient, it’s costly. No matter what business you are running, an e-commerce site, a SaaS platform, or critical internal systems, your PostgreSQL database must be resilient, recoverable, and continuously available. So in short

High Availability (HA) is not a feature you enable; it’s a system you design.

In this blog, we will walk through the important things to consider when setting up a reliable, production-ready HA PostgreSQL system for your applications.

Click through for a variety of things to think about. Most of this will apply to other database systems as well, though specific tools will differ.

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Zone Redundancy in Azure SQL Managed Instance

Published 2025-07-17 by Kevin Feasel

Arun Sirpal explains what zone redundancy is in Azure:

Do you know what happens when you enable zonal redundancy for your SQL managed instance?

Lets define it first (in the context of Business-Critical tier) – zonal redundancy is achieved by placing compute and storage replicas in different availability zones (3) and then using underlying Always On availability group to replicate data changes from the primary instance to standby replicas in other availability zones. 

Availability zones are in the same Azure region, so it works well for high availability but isn’t as good for disaster recovery: if an entire region goes down, zone redundancy won’t help you very much. Also, be aware that you’re paying for what’s running in those three zones because TANSTAAFL.

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High Availability Architecture for PostgreSQL

Published 2025-07-03 by Kevin Feasel

Umair Shahid adds a 9:

Most teams building production applications understand that “uptime” matters. I am writing this blog to demonstrate how much difference an extra 0.09% makes.

At 99.9% availability, your system can be down for over 43 minutes every month. At 99.99%, that window drops to just over 4 minutes. If your product is critical to business operations, customer workflows, or revenue generation, those 39 extra minutes of downtime each month can be the difference between trust and churn.

Click through for some of the tools and practices that can help get you there in PostgreSQL.

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Using Barman to Back Up HA-Enabled PostgreSQL Clusters

Published 2025-07-01 by Kevin Feasel

Semab Tariq reminds us that high availability is not disaster recovery:

Barman is a popular tool in the PostgreSQL ecosystem for managing backups, especially in High Availability (HA) environments. It’s known for being easy to set up and for offering multiple types and modes of backups. However, this flexibility can also be a bit overwhelming at first. That’s why I’m writing this blog to break down each backup option in a simple and clear way, so you can choose the one that best fits your business needs.

Click through for the available options, as well as some recommendations.

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