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Always On Availability Groups

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Adding Managed Instances to SQL Server Distributed Availability Groups

Brent Ozar
Always On Availability Groups, Managed Instances
0
SQL Server Always On Availability Groups help you build a more highly available database server by spanning your database across two or more SQL Server instances. When the primary goes down, the secondary can take over. You can also scale out reads to the secondary servers. Distributed Availability Groups take this a step further and…
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An Expensive Reason To Avoid AGs In Azure

Erik Darling
Always On Availability Groups, Backup and Recovery, CHECKDB and Corruption, Cloud Computing, High Availability, Microsoft Azure, SQL Server
24 Comments
Cash Rules Most people, when they get through paying for Azure, and SQL Server Enterprise Licensing, are left with a hole in their wallet that could only be filled with something that says “Bugatti”, and has a speedometer with an infinity sign at the end. Recently, while working with a client, I found out that…
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New Class: Always On Availability Groups: The Senior DBA’s Field Guide

Brent Ozar
Always On Availability Groups
0
Availability Groups are all the rage right now, especially since they’re included with SQL Server 2016 Standard Edition. Our Availability Groups blog post category is one of the most popular on the site, and in my 4-day Senior DBA class, people have always been asking for more in-depth coverage of clustering and AGs. Let’s get together for a…
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New White Paper: How to Build an Always On Availability Group in Google Compute Engine

Brent Ozar
Always On Availability Groups, Google Compute Engine, SQL Server
21 Comments
You’re a database administrator, Windows admin, or developer. You want to build a Microsoft SQL Server environment that’s highly available, and you’ve chosen to use Always On Availability Groups. Our newest white paper – download In this white paper we built with Google, we’ll show you: How to build your first Availability Group in Google…
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Always On Availability Groups Now Supported in Google Compute Engine

Brent Ozar
Always On Availability Groups, Cloud Computing, Google Compute Engine
6 Comments
I’m excited to finally be able to talk about something Erik, Tara, and I have been working on for the last few months. Here in the SQL Server community, when I mention cloud, you probably think of two companies: Microsoft and Amazon. We’ve been blogging about SQL in AWS for years, and Microsoft throws a…
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When Always On Isn’t: Handling Outages in Your Application

Brent Ozar
Always On Availability Groups, Stack Overflow
6 Comments
Today’s brief Stack Overflow outage reminded me of something I’ve always wanted to blog about: Stack Overflow is in limp-home mode There’s a gray bar across the top that says, “This site is currently in read-only mode; we’ll return with full functionality soon.” That’s not a hidden feature of Always On Availability Groups. Rather, it’s a…
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Availability Groups: More Planned Downtime for Less Unplanned Downtime

Brent Ozar
Always On Availability Groups, Breaking News, SQL Server
10 Comments
I often hear companies say, “We can never ever go down, so we’d like to implement Always On Availability Groups.” Let’s say on January 1, 2016, you rolled out a new Availability Group on SQL Server 2014. It’s the most current version available at the time, and you deploy Service Pack 1, Cumulative Update 4 (released…
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Tara Kizer

Asynchronous Database Mirroring vs. Asynchronous Availability Groups

Tara Kizer
Always On Availability Groups, Database Mirroring, SQL Server
19 Comments
When Database Mirroring came out in SQL Server 2005 Service Pack 1, we quickly dropped Log Shipping as our Disaster Recovery solution. Log Shipping is a good feature, but I can failover with Asynchronous Database Mirroring faster than I can with Log Shipping. When Always On Availability Groups (AG) came out in SQL Server 2012,…
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Updated High Availability and Disaster Recovery Planning Worksheet

Brent Ozar
Always On Availability Groups, Backup and Recovery, Clustering, SQL Server
9 Comments
One of the most popular things in our First Responder Kit is our HA/DR planning worksheet. Here’s page one: Page 1 – how our servers are doing now, versus what the business wants In the past, we had three columns on this worksheet – HA, DR, and Oops Deletes. In this new version, we changed “Oops”…
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Synchronous Always On Availability Groups Is Not Zero Data Loss

Brent Ozar
Always On Availability Groups, Backup and Recovery
20 Comments
In theory, when you configure AlwaysOn Availability Groups with synchronous replication between multiple replicas, you won’t lose data. When any transaction is committed, it’s saved across multiple replicas. That’s the way it works, right? I mean, except when you restart your synchronous replicas, or patch them, or they just stop working for any number of reasons.…
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