Galera on FromDual GmbH

Attribute promotion and demotion in the MariaDB Galera Cluster

oli.sennhauser@fromdual.com (Oli Sennhauser) — Fri, 28 Nov 2025 16:26:48 +0000

In MariaDB master/slave replication there is a feature called attribute promotion/demotion.

How does Galera Cluster behave with many nodes?

oli.sennhauser@fromdual.com (Oli Sennhauser) — Fri, 24 Jan 2025 18:12:55 +0000

Recently I had the opportunity to have a lot of Linux systems (VMs with Rocky Linux 9) from one of our regular Galera Cluster trainings all to myself for a week. And MariaDB 11.4.4 with Galera Cluster was already installed on the machines.

MariaDB Galera Cluster with Corosync/Pacemaker VIP

oli.sennhauser@fromdual.com (Oli Sennhauser) — Wed, 17 Mar 2021 20:26:19 +0000

Sometimes customers want to have a very simple Galera Cluster set-up. They do not want to invest into machines and build up the know-how for load balancers in front of the Galera Cluster.

Keep your Galera Cluster up and running by all means

oli.sennhauser@fromdual.com (Oli Sennhauser) — Fri, 26 Feb 2021 12:15:14 +0000

We see quite often customers complaining that their Galera Cluster is not stable and “crashes” from time to time. As always one has to investigate before rating.

Galera Cluster Release Notes

oli.sennhauser@fromdual.com (Oli Sennhauser) — Fri, 19 Feb 2021 21:32:11 +0000

Source: Github: codership / documentation

Codership Blog for Galera Cluster with release announcements.

MariaDB Galera Cluster Upgrade Path

oli.sennhauser@fromdual.com (Oli Sennhauser) — Fri, 18 Dec 2020 10:47:51 +0000

Because we conduct many customers in MariaDB Galera Cluster upgrades and because these customers sometimes have pretty old MariaDB Galera Cluster set-ups I think it is good to have a rough MariaDB Galera Cluster Upgrade Path.

MySQL - MariaDB migration

oli.sennhauser@fromdual.com (Oli Sennhauser) — Sun, 07 Apr 2019 21:37:32 +0000

More and more MySQL users want to switch from MySQL/Percona Server to MariaDB over time or, more rarely, the other way around. This is mostly caused by the change of the default in the Linux Distributions (RHEL/CentOS 7, SLES 12, Debian 8) to MariaDB.
Up to MySQL/MariaDB 5.5 everything was quite easy, both Branches claim to be a drop-in replacement of each other. But after the separation into different forks (MariaDB 10.0 ff. vs. MySQL 5.6 ff.) we expect more and more problems migrating from one branch to the other what we call sidegrade.
Percona Server code is genetically closer to MySQL than MariaDB. So we expect to see less problems on this sidegrade.

Short term notice: Percona XtraDB Cluster training in English 7/8 February 2018 in Germany

oli.sennhauser@fromdual.com (Oli Sennhauser) — Fri, 19 Jan 2018 17:05:29 +0000

FromDual offers short term a Percona XtraDB Cluster and MySQL Galera Cluster training (2 days) in English.

MariaDB, Galera and MySQL training class schedule

oli.sennhauser@fromdual.com (Oli Sennhauser) — Tue, 29 Dec 2015 16:39:58 +0000

We offer our MySQL and MariaDB trainings together with well-respected training organizations: The Linuxhotel in Essen (Germany), the Heinlein Academy in Berlin (Germany) and GFU Cyrus AG in Cologne (Germany). Our own MySQL and MariaDB training classes are hold in the building of the HSO in Zürich (Switzerland).

Limitations of Galera Cluster

oli.sennhauser@fromdual.com (Oli Sennhauser) — Sat, 11 Jul 2015 17:07:40 +0000

If and how to use Galera Cluster for MySQL has been described already by many others…

Logging Galera Cluster conflicts

oli.sennhauser@fromdual.com (Oli Sennhauser) — Sat, 11 Apr 2015 12:30:54 +0000

We typically suggest our customers to use our MySQL/Galera Cluster my.cnf configuration template to avoid MySQL configuration and performance problems.

Galera Cluster last inactive check and VMware snapshots

oli.sennhauser@fromdual.com (Oli Sennhauser) — Sat, 11 Apr 2015 11:46:36 +0000

From time to time we see at Galera Cluster customer engagements the following, for me scary, warning in the MySQL error log:

failed MySQL DDL commands and Galera replication

oli.sennhauser@fromdual.com (Oli Sennhauser) — Tue, 09 Dec 2014 15:45:23 +0000

We have recently seen a case where the following command was executed on a Galera Cluster node:

Ugly way to install MySQL Galera Cluster 5.6 on Ubuntu 14.04

oli.sennhauser@fromdual.com (Oli Sennhauser) — Mon, 20 Oct 2014 21:26:22 +0000

I wanted to install MySQL Galera Cluster 5.6 on the new Ubuntu 14.04 with provided packages. It was a bit tricky to make it work.

FromDual: Tools for MySQL and Galera - Backup - Monitoring - Operations

oli.sennhauser@fromdual.com (Oli Sennhauser) — Sun, 27 Jul 2014 10:46:18 +0000

FromDual tools provide valuable additional functionality which facilitate and optimize daily operations of your MySQL databases. Since our last newsletter a lot of things have changed in the FromDual tools.

Replication channel failover with Galera Cluster for MySQL

oli.sennhauser@fromdual.com (Oli Sennhauser) — Thu, 19 Jun 2014 07:05:38 +0000

Sometimes it could be desirable to replicate from a Galera Cluster to a single MySQL slave or to an other Galera Cluster. Reasons for this measure could be:

Why FromDual customers are using Galera Cluster for MySQL

oli.sennhauser@fromdual.com (Oli Sennhauser) — Thu, 20 Feb 2014 12:34:05 +0000

We are very satisfied with the functionality and the launch. The entire Cluster is running absolutely stable. This is a significant advantage for our customers because we are able to offer our services without interruption. We will use Galera in further projects and convert our existing Master/Slave installations.

What are the costs of one hour MySQL downtime?

oli.sennhauser@fromdual.com (Oli Sennhauser) — Tue, 17 Dec 2013 14:59:10 +0000

Hello,

there are companies which earn tens of thousands of Euros per hour with their MySQL databases. Other companies operate their ERP system on MySQL, to which 1000 employees are attached to. Is the database down 1000 people are not working any more until the system is working again! Downtime costs starting at EUR 30'000.- per hour upwards.

Galera Cluster for MySQL

oli.sennhauser@fromdual.com (Oli Sennhauser) — Wed, 11 Dec 2013 12:08:32 +0000

Features

Galera is a synchronous multi-master replication Cluster for MySQL/InnoDB databases, having features like:

Upgrade from Galera Cluster 2.x to 3.0

oli.sennhauser@fromdual.com (Oli Sennhauser) — Thu, 24 Oct 2013 21:25:22 +0000

Introduction

Codership announced from weeks ago introducing the Galera Cluster new release 3.0 having many bug fixes, performance enhancements plus the main purpose which is working with MySQL 5.6. In this article, I’ll go through the upgrade steps from Galera 2.x to the new release 3.0, but at the time of writing this article - as mentioned in the Codership release notes - THIS IS A BETA QUALITY RELEASE FOR TESTING PURPOSES. NOT RECOMMENDED FOR PRODUCTION YET.

Galera Load Balancer Documentation

oli.sennhauser@fromdual.com (Oli Sennhauser) — Sat, 17 Aug 2013 22:08:40 +0000

About

glbd is a simple TCP connection balancer made with scalability and performance in mind. It was inspired by pen, but unlike pen its functionality is limited only to balancing generic TCP connections.

Galera Arbitrator (garbd)

oli.sennhauser@fromdual.com (Oli Sennhauser) — Sat, 17 Aug 2013 16:59:38 +0000

It took me quite a while to find out how the beast Galera Arbitrator (garbd) works. To safe your time here a short summary:

Unbreakable MySQL Cluster with Galera and Linux Virtual Server (LVS)

oli.sennhauser@fromdual.com (Oli Sennhauser) — Thu, 13 Jun 2013 17:13:47 +0000

Recently we had to set-up a 3-node Galera Cluster with a Load Balancer in front of it. Because Galera Cluster nodes (mysqld) still reply to TCP requests on port 3306 when they are expelled from the Cluster it is not sufficient to just leave it to the Load Balancer to check the port if a Galera node is properly running or not.

Switching from MySQL/MyISAM to Galera Cluster

oli.sennhauser@fromdual.com (Oli Sennhauser) — Tue, 12 Mar 2013 08:23:36 +0000

Switching from MySQL/MyISAM to Galera Cluster requires that all tables (except those from the mysql, information_schema and performance_schema) are using the InnoDB Storage Engine.

Bootstrapping Galera Cluster the new way

oli.sennhauser@fromdual.com (Oli Sennhauser) — Tue, 05 Feb 2013 19:18:25 +0000

A while ago it was pretty inconvenient to start a complete Galera Cluster from scratch. Rolling restart an such things are already working well but bootstrapping was a pain.

Artikel über MySQL im neuen iX

oli.sennhauser@fromdual.com (Oli Sennhauser) — Thu, 20 Sep 2012 15:12:59 +0000

Hallo MySQL Gemeinde,

Im neuen iX (2012-10) hat es zwei nette Artikel über: MySQL HA-Lösungen (S. 116) und MySQL 5.6 (S. 66).

Galera Cluster Nagios Plugin

oli.sennhauser@fromdual.com (Oli Sennhauser) — Fri, 14 Sep 2012 10:49:59 +0000

Based on customer feedback we have decided to add a plugin Galera Cluster for MySQL to our MySQL Nagios/Icinga Plugins.

Galera Cluster discussions at FrOSCon 2012

oli.sennhauser@fromdual.com (Oli Sennhauser) — Mon, 27 Aug 2012 17:18:40 +0000

During and after Henriks great talk about Galera Cluster at the FrOSCon 2012 in St. Augustin we found 2 important things related to Galera Cluster for MySQL:

DOAG SIG MySQL - Replication: September 4, 2012 in Hamburg

oli.sennhauser@fromdual.com (Oli Sennhauser) — Mon, 30 Jul 2012 15:11:17 +0000

On Tuesday, September 4, 2012 the next DOAG SIG MySQL meeting will take place in Hamburg (Germany) with the topic Replication.

FromDual Newsletter Spring 2012

oli.sennhauser@fromdual.com (Oli Sennhauser) — Fri, 27 Apr 2012 11:12:50 +0000

Dear MySQL User,

With this newsletter we bring you up to date about MySQL and our Services.

MySQL and Galera Load Balancer (GLB)

oli.sennhauser@fromdual.com (Oli Sennhauser) — Sat, 07 Apr 2012 10:10:21 +0000

When you install a Galera Cluster for MySQL for High Availability (HA) it is not enough to install the Database Cluster to achieve this goal. You also have to make the application aware of this HA functionality. This is typically done with some kind of load balancing mechanism between the database and the application.

Codership partners with FromDual to offer consulting and support services for Galera Cluster for MySQL

oli.sennhauser@fromdual.com (Oli Sennhauser) — Sun, 19 Feb 2012 09:56:45 +0000

Helsinki, Finland, Uster, Switzerland – February 18, 2012 – Codership, the provider of Galera Cluster for MySQL, and FromDual, a MySQL consulting company, today announced collaboration to offer Galera Cluster technology and related support and consulting services for Galera users all over the world, especially in German speaking countries Germany, Austria and Switzerland (DACH). Galera Cluster is a synchronous, true multi-master replication cluster for MySQL using the well known InnoDB storage engine. Customers can deploy Galera Cluster locally in LAN environments, as geo-clusters over the WAN or as virtual cluster in the cloud.

I prefer MySQL binary tar balls with Galera...

oli.sennhauser@fromdual.com (Oli Sennhauser) — Wed, 08 Feb 2012 15:13:18 +0000

In my set-ups I have different MySQL versions (MySQL 5.0, 5.1, 5.5 and 5.6, Percona Server 13.1 and 24.0, MariaDB 5.2.10, 5.3.3, Galera 1.0, 1.1 and 2.0) running in parallel at the same time.

Rolling upgrade of Galera 1.0 to 1.1

oli.sennhauser@fromdual.com (Oli Sennhauser) — Wed, 14 Dec 2011 15:38:27 +0000

A few days ago Codership announced their new version Galera v1.1 - synchronous Replication Cluster for MySQL. Before we look at the new feature of Rolling Online Schema Upgrade (OSU) we have a look at how to upgrade to the new Galera release.

Migrating from MySQL Master-Master Replication to Galera Multi-Master Replication

oli.sennhauser@fromdual.com (Oli Sennhauser) — Fri, 02 Dec 2011 14:48:58 +0000

Introduction

Galera is a synchronous Multi-Master Replication for MySQL. It is therefore in competition with several other MySQL architectures:

Building Galera Replication from Scratch

oli.sennhauser@fromdual.com (Oli Sennhauser) — Sun, 13 Nov 2011 12:29:54 +0000

Introduction

MySQL/Galera synchronous Multi-Master Replication consists of 2 parts:

The wsrep patches for MySQL (codership-mysql) and
the Galera Replication Plugin (galera).

If you do not want to download the prepared binaries you can build it on you own.
First you have to download the native MySQL sources, then patch it with the Galera wsrep patches and compile it. In a second step you have to build the Galera Plugin.

Galera - Synchronous Multi-Master Replication Cluster for MySQL/InnoDB

oli.sennhauser@fromdual.com (Oli Sennhauser) — Fri, 23 Sep 2011 11:07:03 +0000

Galera features

Galera provides the following features:

Synchronous replication
Active/active multi-master topology
Read and write to any cluster node
Automatic membership control, failed nodes drop from the cluster
Automatic node joining
True parallel row level replication
Direct client connections
Drop-in replacement for native MySQL

Galera benefits

Benefits using Galera Replication:

MariaDB, Galera and MySQL Support

oli.sennhauser@fromdual.com (Oli Sennhauser) — Wed, 01 Dec 2010 12:26:19 +0000

FromDual is a support partner of MariaDB plc, Codership Oy and Oracle Corporation. This gives us the opportunity to offer you customized enterprise support subscriptions for your mission-critical MariaDB, Galera or MySQL databases for all three vendors.

Limitations of MySQL

oli.sennhauser@fromdual.com (Oli Sennhauser) — Mon, 15 Mar 2010 11:01:40 +0000

Often asked but informations are spread around: The limitations of MySQL.

Systemd related stuff for MariaDB and MySQL

oli.sennhauser@fromdual.com (Oli Sennhauser) — Fri, 06 Jan 2023 19:05:06 +0100

Systemd Notizen

Systemd paged per default nach less. Das ist ungewohnt und doof, weil es gegen allgemeines Linux-Verhalten verstösst. Abhilfe schafft:

Linux Container with Incus for focmm unit testing

oli.sennhauser@fromdual.com (Oli Sennhauser) — Thu, 13 Oct 2022 19:11:40 +0200

Currently we are in the testing phase of the next release of our Ops Center (focmm). This testing is quite complex because it includes testing the interaction of various different components like a MariaDB Galera Cluster, a Galera Load Balancer, a virtual IP, etc.

MariaDB and MySQL PERFORMANCE_SCHEMA Hints

oli.sennhauser@fromdual.com (Oli Sennhauser) — Sun, 14 Jul 2013 09:29:09 +0200

Accounts not properly closing connections
Unused indexes
Who created temporary (disk) tables
Accounts which never connected since last start-up
Users which never connected since last start-up
Totally unused accounts (never connected since last restart and not used to check Stored Program or View privileges) since last start-up
SHOW FULL PROCESSLIST
Storage Engines per schema
Tables without a Primary Key
Bad SQL queries of users
SHOW PROFILE in PERFORMANCE_SCHEMA
SELECT, INSERT, UPDATE and DELETE per table
Top long running queries
Tables never written to
DML, DDL and DCL per account
Finding syntactically wrong/erroneous MySQL queries
Finding queries served by MySQL Query Cache
Grant access to sys schema to another user
Grant access to PERFORMANCE_SCHEMA schema to another user
Find InnoDB Locks
Find Metadata Locks
What did a Connection before sleeping?
How many statements did another (sleeping) connection?
MyISAM locking
Connections per user
Connections per user and IP
Accounts which could not connect or with connection errors
Temporary tables filling my disk
Who is writing to the binary log
Average binlog transaction size
Result size of SELECT statement
Find open long running transactions

MariaDB

On MariaDB you have to enable the Performance Schema first before use:

Galera on FromDual GmbH

Attribute promotion and demotion in the MariaDB Galera Cluster

How does Galera Cluster behave with many nodes?

MariaDB Galera Cluster with Corosync/Pacemaker VIP

Keep your Galera Cluster up and running by all means

Galera Cluster Release Notes

MariaDB Galera Cluster Upgrade Path

MySQL - MariaDB migration

Table of Contents

Short term notice: Percona XtraDB Cluster training in English 7/8 February 2018 in Germany

MariaDB, Galera and MySQL training class schedule

Limitations of Galera Cluster

Logging Galera Cluster conflicts

Galera Cluster last inactive check and VMware snapshots

failed MySQL DDL commands and Galera replication

Ugly way to install MySQL Galera Cluster 5.6 on Ubuntu 14.04

FromDual: Tools for MySQL and Galera - Backup - Monitoring - Operations

Replication channel failover with Galera Cluster for MySQL

Why FromDual customers are using Galera Cluster for MySQL

What are the costs of one hour MySQL downtime?

Galera Cluster for MySQL

Features

Upgrade from Galera Cluster 2.x to 3.0

Table of Contents

Introduction

Galera Load Balancer Documentation

About

Galera Arbitrator (garbd)

Unbreakable MySQL Cluster with Galera and Linux Virtual Server (LVS)

Switching from MySQL/MyISAM to Galera Cluster

Bootstrapping Galera Cluster the new way

Artikel über MySQL im neuen iX

Galera Cluster Nagios Plugin

Galera Cluster discussions at FrOSCon 2012

DOAG SIG MySQL - Replication: September 4, 2012 in Hamburg

FromDual Newsletter Spring 2012

MySQL and Galera Load Balancer (GLB)

Table of Contents

Codership partners with FromDual to offer consulting and support services for Galera Cluster for MySQL

I prefer MySQL binary tar balls with Galera...

Rolling upgrade of Galera 1.0 to 1.1

Migrating from MySQL Master-Master Replication to Galera Multi-Master Replication

Introduction

Building Galera Replication from Scratch

Introduction

Galera - Synchronous Multi-Master Replication Cluster for MySQL/InnoDB

Galera features

Galera benefits

MariaDB, Galera and MySQL Support

Limitations of MySQL

Systemd related stuff for MariaDB and MySQL

Table of Contents

Systemd Notizen

Linux Container with Incus for focmm unit testing

MariaDB and MySQL PERFORMANCE_SCHEMA Hints

Table of Contents

MariaDB