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Become a MySQL DBA blog series - Troubleshooting Galera cluster issues - part 2

This is part 2 of our blog on how to troubleshoot Galera cluster - SST errors, and problems with network streaming. In part 1 of the blog, we covered issues ranging from node crashes to clusters that won’t restart, network splits and inconsistent data. Note that the issues described are all examples inspired from real life incidents in production environments.

Become a MySQL DBA blog series - Troubleshooting Galera cluster issues - part 1

In this blog post, we are going to show you some examples of things that can go wrong in Galera - inexplicable node crashes, network splits, clusters that won’t restart and inconsistent data. We’ll take a look at the data stored in log files to diagnose the problems, and discuss how we can deal with these.

nginx as Database Load Balancer for MySQL or MariaDB Galera Cluster

Nginx is well-known for its ability to act as a reverse-proxy with small memory footprint. It usually sits in the front-end web tier to redirect connections to available backend services, provided these passed some health checks. Using a reverse-proxy is common when you are running a critical application or service that requires high availability. It also distributes the load equally among the backend services.

Become a MySQL DBA blog series - Optimizer Hints for faster query execution

MySQL uses a cost-based optimizer to determine the best way to execute a query. It usually does a great job, but not all the time. There are different reasons for that. In some cases, it might not have enough information about the data and plan queries in a non-optimal way.

Become a MySQL DBA blog series - Using Explain to improve SQL Queries

When it comes to the query tuning, EXPLAIN is one the most important tool in the DBA’s arsenal. Why is a given query slow, what does the execution plan look like, how will JOINs be processed, is the query using the correct indexes, or is it creating a temporary table? In this blog post, we’ll look at the EXPLAIN command and see how it can help us answer these questions.

Become a MySQL DBA blog series - Database Indexing

An index is a data structure that sorts a number of records on one or more fields, and speeds up data retrieval. This is to avoid scanning through the disk blocks that a table spans, when searching through the database. So, what kind of indexes are available in MySQL and how do we use them to get the most performance? This will be the topic for this blog.

High Availability MySQL on cPanel with Galera Cluster

In this blog post, we will show you how to integrate Galera Cluster for MySQL into cPanel to provide a high availability database hosting solution. By default, cPanel uses localhost to host the MySQL databases created by cPanel users. It is not uncommon to find MySQL to be the culprit when it comes to overloading the server. By having a remote MySQL server or cluster, we can offload some of the burden and increase the availability of other important services on the server.

Wordpress Application Clustering using Kubernetes with HAProxy and Keepalived

In this blog post, we’re going to play with Kubernetes application clustering and pods. We’ll use Wordpress as the application, with a single MySQL server. We will also have HAProxy and Keepalived to provide simple packet forwarding (for external network) with high availability capability.

Become a MySQL DBA blog series - Deep Dive SQL Workload Analysis using pt-query-digest

In our previous post, we showed you how to interpret reports generated by pt-query-digest. Today we’d like to cover some of its more advanced features, as it is a pretty extensive tool with lots of functionality. We’ll also show you what information you should be looking for, and how to derive conclusions based on that data. 

Webinar Replay & Slides: Become a MySQL DBA - Schema Changes for MySQL Replication & Galera Cluster

Thanks to everyone who joined us for our recent live webinar on ‘Schema Changes for MySQL Replication & Galera Cluster’ led by Krzysztof Książek, Senior Support Engineer at Severalnines. The replay and slides to the webinar are now available to watch and read online via the links below.