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[Video] Installing SQL Server Updates in an Availability Group, and Save 50% on Training

Brent Ozar
Always On Availability Groups, Videos
2 Comments
This week, we’re sharing Instant Replay videos from our training classes. Today’s Instant Replay is Edwin Sarmiento talking about how he approaches applying service packs and cumulative updates on Always On Availability Groups: That video is part of the Instant Replay recordings of Edwin’s extensive live 3-day Senior DBA’s Guide to Always On Availability Groups.…
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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
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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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Direct Seeding: I’ve Got A Wizard And You Don’t

Erik Darling
Always On Availability Groups, High Availability
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4 Comments
A commenter commented That the “New AG Wizard” in SSMS 2017 had surfaced the Direct Seeding mode for AGs. I was pretty psyched about this because I think it’s a great feature addition to AGs that can solve for a pretty big hump that people run into when they create databases regularly. It used to…
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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
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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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When Always On Isn’t: Handling Outages in Your Application

Brent Ozar
Always On Availability Groups, Stack Overflow
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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
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9 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
15 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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Availability Group Direct Seeding: Mind Your Backup Jobs

Erik Darling
Always On Availability Groups, Backup and Recovery, SQL Server
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7 Comments
I’ll get right to the point While you’re Direct Seeding, you have to be careful with any other full or differential backup jobs running on the server. This is an artifact of the Direct Seeding process, but it’s one you should be aware of up front. In the screencap below, courtesy of sp_whoisactive there’s a…
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Availability Group Direct Seeding: TDE’s Frenemy

Erik Darling
Always On Availability Groups, SQL Server
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8 Comments
From the Mailbag In another post I did on Direct Seeding, reader Bryan Aubuchon asked if it plays nicely with TDE. I’ll be honest with you, TDE is one of the last things I test interoperability with. It’s annoying that it breaks Instant File Initialization, and mucks up backup compression. But I totally get the…
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Availability Group Direct Seeding: Extended Events and DMVs

Erik Darling
Always On Availability Groups, SQL Server
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16 Comments
As of this writing, this is all undocumented I’m super interested in this feature, so that won’t deter me too much. There have been a number of questions since Availability Groups became a thing about how to automate adding new databases. All of the solutions were kind of awkward scripts to backup, restore, join, blah…
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Availability Group Direct Seeding: How to fix a database that won’t sync

Erik Darling
Always On Availability Groups
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12 Comments
This post covers two scenarios You either created a database, and the sync failed for some reason, or a database stopped syncing. Our setup focuses on one where sync breaks immediately, because whatever it’s my blog post. In order to do that, I set up a script to create a bunch of databases, hoping that…
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SQL Server 2016: Availability Groups, Direct Seeding, and You.

Erik Darling
Always On Availability Groups, SQL Server
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39 Comments
One of my least favorite things about Availability Groups Well, really, this goes for Mirroring and Log Shipping, too. Don’t think you’re special just because you don’t have a half dozen patches and bug fixes per CU. Hah. Showed you! Where was I? Oh yeah. I really didn’t like the backup and restore part. You…
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Synchronous Always On Availability Groups Is Not Zero Data Loss

Brent Ozar
Always On Availability Groups, Backup and Recovery
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19 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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