Because it's easier with two - Availability Groups

Nothing to lose if there is a system failure?! The dream of every company. High availability is not only important, but also absolutely necessary. But is high availability really possible? Yes.

In this article, we would therefore like to briefly introduce you to the always-on availability group concepts that are important for configuring and managing one or more availability groups in SQL Server.

What is an Always On availability group?

The high availability architecture in Azure SQL Database and SQL Managed Instance ensures that your database is up and running at least 99.99 percent of the time, without you having to worry about the impact of maintenance and outages. Azure automatically handles important maintenance tasks such as backups, Windows and Azure SQL upgrades, as well as unplanned events such as hardware, software or network failures.

The high-availability solution should ensure that data for which a commit has been executed is never lost due to errors, that maintenance processes do not affect your workload and that the database does not represent a single point of failure in the software architecture.

There are two architecture models for high availability:

The availability groups are based on the separation of the computer and storage levels. It is based on the high availability and reliability of the remote storage level. This architecture is designed for budget-bound business applications that can tolerate certain performance losses during maintenance work. However, a small interruption must be expected in the event of a failure, as the second server takes some time to load. The two servers must be paid for separately.

The failover cluster is based on a cluster of database engine processes. This is based on the fact that there is always a quorum of available database engine nodes. This architecture is designed for mission-critical applications with high I/O performance and a high transaction rate; it guarantees minimal performance degradation for your workload during maintenance activities. However, this variant requires the Enterprise Edition, which is priced very differently from the Standard Edition. However, it can do everything that the standard edition can do.

Why should you get a Microsoft SQL high availability solution?

This system means that your system is always backed up by two servers. As soon as one fails, the second server is used, which has all the information that the first server had. This means that you can continue to work unhindered despite a system failure without losing your data.