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53 blog posts in 13 categories

HA for MySQL and MariaDB - Comparing Master-Master Replication to Galera Cluster

Replication and Galera Cluster are both widely used to implement high availability for MySQL/MariaDB, but when should you pick one over the other? What are the limitations of each solution, and what are the trade offs?
In this blog post, we will look at the differences in terms of data consistency, conflict resolution, failover, node provisioning and robustness.

MySQL on Docker: Multiple Delayed Replication Slaves for Disaster Recovery with Low RTO

A delayed replication slave is useful in recovering from accidental data deletion. But how long should the delay be? Too short delay might not be enough for you to get to a terminal and stop an offending query. Too long delay means a long recovery time when catching up.

This blog post shows how to deploy multiple MySQL delayed slaves on one single physical host with Docker, and shows some of the recovery scenarios.

Effective Monitoring of MySQL Replication with SCUMM Dashboards - Part 2

The new release of ClusterControl 1.7.0 introduces SCUMM (Severalnines ClusterControl Unified Management and Monitoring). Monitoring MySQL with SCUMM Part 1 adds the efficiency and productivity for a MySQL Database Administrator.

MySQL on Docker: Running ProxySQL as a Helper Container on Kubernetes

When your application containers are orchestrated and managed by Kubernetes, you might want to use ProxySQL to better take advantage of your distributed database service running on replication or Galera. In this post, we are going to cover how to run ProxySQL on Kubernetes as a helper container in a pod.

An Overview of Volume Level Replication for PostgreSQL Using DRBD

Volume level replication is a generic approach that not only applies to PostgreSQL, but also all relational databases. In this blog, we’ll show you how to use DRBD,  a distributed replicated storage system for Linux, to replicate your database for high availability.

Introduction to Failover for MySQL Replication - the 101 Blog

With this blog post we aim to give you an introduction to failover handling in MySQL & MariaDB by discussing what failover is, why it is unavoidable and what the difference is between failover and switchover. We also discuss the failover process in its most generic form and touch a bit on different issues that you will have to deal with in relation to the failover process.

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.

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.

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 Recover Galera Cluster or MySQL Replication from Split Brain Syndrome

Split brain syndrome is a state where a cluster of nodes is partitioned into smaller clusters of equal numbers of nodes, and each cluster believes it is the active cluster. This is a harmful state, as data is changed on a partition, without being replicated to the other. This blog post describes how to prevent a split brain from happening, and what can be done if it does happen.

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