Severalnines Blog
The automation and management blog for open source databases

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579 blog posts in 13 categories

Asynchronous Replication Between MySQL Galera Clusters - Failover and Failback

Asynchronous replication places no low latency demands on the network, so it is possible to keep Galera Clusters in sync even when they are thousands of miles apart and utilise low-cost connections. We effectively can achieve a global system of loosely-coupled clusters. However, managing the global state translates into managing failover and failback operations at both node and cluster level.

Failover for PostgreSQL Replication 101

Failover is a procedure that we hope we won’t have to use, but we must know how it works. In this blog, we will be cover the basic definitions of failover in PostgreSQL replication, and some example scenarios where failover can be useful.

6 Common Failure Scenarios for MySQL & MariaDB, and How to Fix Them

Database failures can happen at different levels, from schema corruption on an individual server to hardware or even an entire datacenter going down. So how do we troubleshoot and fix these? In this blogpost, we will walk through 6 different failure scenarios and see how we recovery from them.

Controlling Replication Failover for MySQL and MariaDB with Pre- or Post-Failover Scripts

Databases are a part of a wider mesh of infrastructure components, and as such, failover usually has some impact on more than just the database. Therefore, the failover software needs a mechanism to orchestrate changes across the infrastructure. This blog post describes how ClusterControl can be integrated with external infrastructure and tools, through the use of scripts executed during failover process.

More of My Favorite PostgreSQL Queries - and Why They Also Matter

This is the follow up to the popular blog ‘My favourite PostgreSQL queries and why they matter’. This new blog focusses on a particular query, multi-row UPDATE with a single CASE expression, and makes comparisons between that particular query, and one involving multiple single UPDATE statements.

ClusterControl Release 1.6.2: New Backup Management and Security Features for MySQL & PostgreSQL

This blog provides an overview of the new Backup Management and Security & Compliance features for MySQL & PostgreSQL in the ClusterControl 1.6.2 release.

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How to Control Replication Failover for MySQL and MariaDB

Automated failover is a critical functionality in a MySQL or MariaDB replication setup, involving master-promotion and reslaving. Now, not all slaves are good master candidates, so how do you control which node gets picked? This blog introduces whitelists and blacklists.

How to perform Schema Changes in MySQL & MariaDB in a Safe Way

This blog describes best practices to make your database schema changes in MySQL and MariaDB flawless. We will walk you through different scenarios and recomment some approaches for each.

Custom Trigger Based Upgrades for PostgreSQL

This blog provides an overview of custom trigger based upgrades for PostgreSQL; and some insight into how computer game strategies can be lessons for database administration life.

Galera Cluster Recovery 101 - A Deep Dive into Network Partitioning

Galera automatic node provisioning and membership control simplifies database cluster operation and improves the reliability of its replication technology. In this blog post, we are diving into the Galera recovery process in events where network partitioning happens.