High Availability

Microsoft SQL Server 2012 Always On AGs at StackOverflow

Last Updated February 9, 2017

Always On Availability Groups, SQL Server, Stack Overflow

I recently finished helping the StackExchange team migrate their SQL Server 2008 infrastructure to SQL Server 2012. These servers power StackOverflow, DBA.StackExchange.com, the new AskPatents partnership with the US Patent and Trademark Office, and hundreds of other Q&A sites that together form one of the biggest web site networks. It’s one of the most visible…

Before You Fail Over a SQL Server Always On Availability Group

Last Updated February 9, 2017

Brent Ozar

Always On Availability Groups

Think fast! When it’s time to do a manual failover with SQL Server 2012 AlwaysOn Availability Groups, we need to make a few decisions and perform a few tasks as quickly as possible to get the business back up and running. Here’s what you need to consider ahead of time so you can stay calm,…

AlwaysOn Availability Groups in AWS Revisited

Last Updated February 13, 2017

Jeremiah Peschka

Always On Availability Groups, Amazon Web Services (AWS)

If you’ve ever wanted to use the cloud for a DR site, there’s good news: as of this week you can use AlwaysOn Availability Groups and set up an asynchronous replica of your data into Amazon Web Services (AWS). If you’re already in the cloud, or if you were holding off, this means that you…

Why Your SQL Server’s Network Connection Matters

Last Updated February 9, 2017

Brent Ozar

Always On Availability Groups, Clustering

If you’re using SQL Server 2012’s hot new AlwaysOn Availability Groups feature, your databases will go offline when your network connection does – even if you’re using asynchronous replication. This is not a bug. This is working as designed – and it’s important to understand the underlying concepts. Nothing to see here, I'm just going…

Everything You Know About Clustering is Wrong

Last Updated February 9, 2017

Brent Ozar

Clustering

Remember that weirdo in high school who had no social skills? Couldn’t get a date, worked at the fast food joint as a fry cook, face covered with zits – you know the one. Okay, actually, it was us. Anyway, the point is, we got our act together, didn’t we? So did Windows Failover Clustering. …

SQL Server Always On Availability Groups in AWS

Last Updated February 9, 2017

Jeremiah Peschka

Always On Availability Groups, Cloud Computing

Many companies are investigating a move into cloud hosting. With the recent release of SQL Server 2012, these very same companies are also looking at a migration to SQL Server 2012 to take advantage of readable secondaries. Combining Amazon Web Services and SQL Server 2012 seems like a perfect match. Unfortunately, there are some gotchas,…

Why Availability Groups Make It Cool Again to Be a Sysadmin

Last Updated February 9, 2017

Kendra Little

Always On Availability Groups

Professions go through phases. Some skills are highly valued for a while, then go out of fashion. Just like leg warmers and skinny jeans, some skills come back into style when you least expect it. Sideburns are back Database Administrators Started Out in the Server Room In the early days, most database administrators started out…

Where to Run DBCC on Always On Availability Groups

Last Updated February 9, 2017

Brent Ozar

Always On Availability Groups

With SQL Server 2012’s new AlwaysOn Availability Groups, we have the ability to run queries, backups, and even DBCCs on database replicas. But should we? Paul Randal (Blog – @PaulRandal) covered this issue in today’s SQLskills Insider newsletter, and he says: “It’s not checking the I/O subsystem of the log shipping primary database – only…

An Introduction to SQL Server Clusters

Last Updated February 9, 2017

Kendra Little

Clustering

337

The options for high availability can get confusing. I was lucky enough to begin working with SQL Server clusters early in my career, but many people have a hard time finding simple information on what a cluster does and the most common gotchas when planning a cluster. Today, I’ll tell you what clusters are, what they’re…

My 3 Favorite Connection String Tips

Last Updated February 9, 2017

Brent Ozar

Always On Availability Groups, Development

Connection strings – boring topic, right? Well, it turns out there’s a few things that can save your behind. Tip 1: Build your application with 3 connection strings. If you want to scale, write your application from the start with 3 different connection strings: Writes and real-time reads Reads that can tolerate data older than…

SQL Server in EC2

Last Updated February 9, 2017

Jeremiah Peschka

Always On Availability Groups, Amazon Web Services (AWS)

The cloud is robust and reliable. The cloud solves all of our scaling needs. The cloud makes my poop smell like roses. While all of these statements are theoretically true it takes some effort to make them true in reality, especially when a database is involved. Who Is Deploying SQL Server in EC2? A question…

How to Set Up SQL Server 2012 Always On Availability Groups

Last Updated March 5, 2017

Brent Ozar

Always On Availability Groups

251

Before we get started, we need to talk about something. I’m going to be using the C word – that’s right, Clustering. Deep, calming breaths. Relax. We can do this, you and me. This isn’t the old-school clustering with shared disks, heartbeat networks, and hardware compatibility lists. This is just another feature you’re going to…

Scaling Up or Scaling Out? Part Two

Last Updated February 9, 2017

Brent Ozar

Always On Availability Groups

In part 1 of this post, I covered how SQL Server handles scaling up. We talked about how quickly it becomes expensive to add more CPU power, memory, and storage throughput to our database servers. Today, we’re going to focus on a different way to scale. When most folks talk about scaling out SQL Server,…

SQL Server 2012 AlwaysOn Availability Groups Rock

Last Updated February 9, 2017

Brent Ozar

Always On Availability Groups

105

SQL Server 2012 brings huge improvements for scaling out and high availability. To put these changes into perspective, let’s take a trip down memory road first and look at the history of database mirroring. SQL Server 2005 first introduced mirroring, although it wasn’t fully supported until a service pack. In many ways, mirroring beat the…

The Cost of Log Shipping SQL Server to Amazon S3

Last Updated February 13, 2017

Brent Ozar

Log Shipping, SQL Server

Want to know how much it’ll cost to back up your database transaction logs to Amazon S3? I’ll show you with a snippet of T-SQL. Note the parameters at the top for retention periods. The defaults assume one full backup weekly. DBAs would normally want to do full backups more often, but when you’re paying…

Mirrors aren’t backups

Last Updated February 9, 2017

Brent Ozar

Architecture, Backup and Recovery, Database Mirroring

Are you using any of these technologies as a method of database protection? Database mirroring (keeping two database servers synchronized with the same data via SQL 2005/2008) Replication (copying records between databases) Log shipping (copying log files to another server and restoring them immediately) SAN-based mirroring (storing two copies of your database on two different…

High Availability

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