Galera Cluster 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.

Upgrading from MariaDB 10.4 to MariaDB 10.5 Galera Cluster

oli.sennhauser@fromdual.com (Oli Sennhauser) — Sat, 21 Nov 2020 20:58:09 +0000

Because upgrading from MariaDB 10.4 to MariaDB 10.5 (non-clustered) seems not to be a problem
[ 1
] we take the challenge and try to create a receipt based on the MariaDB 10.3 to MariaDB 10.4 Galera Cluster upgrade documentation
[ 3
]:

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.

Uptime of a MariaDB Galera Cluster

oli.sennhauser@fromdual.com (Oli Sennhauser) — Fri, 15 Mar 2019 17:58:28 +0000

A while ago somebody on Google Groups asked for the Uptime of a Galera Cluster. The answer is easy… Wait, no! Not so easy… The uptime of a Galera Node is easy (or not?). But Uptime of the whole Galera Cluster?

Galera Cluster and Antivirus Scanner on Linux

oli.sennhauser@fromdual.com (Oli Sennhauser) — Tue, 12 Dec 2017 22:51:07 +0000

Today we had to investigate in a very strange behaviour of IST and SST on a MariaDB Galera Cluster.

Galera Load Balancer the underestimated wallflower

oli.sennhauser@fromdual.com (Oli Sennhauser) — Thu, 21 Sep 2017 15:25:18 +0000

There are some pretty sophisticated Load Balancers for Galera Clusters setups out in the market (ProxySQL, MaxScale, HAproxy, …). They have many different exotic features. You can nearly do everything with them. But this comes at the cost of complexity. Non of them is simple any more.

Is your MySQL software Cluster ready?

oli.sennhauser@fromdual.com (Oli Sennhauser) — Fri, 27 Jan 2017 18:19:56 +0000

When we do Galera Cluster consulting we always discuss with the customer if his software is Galera Cluster ready. This basically means: Can the software cope with the Galera Cluster specifics?

How to move InnoDB-Logfiles on a Galera Cluster

oli.sennhauser@fromdual.com (Oli Sennhauser) — Wed, 05 Oct 2016 10:35:35 +0000

Somebody recently asked, what they had to do, if they wanted to move their InnoDB-Logfiles back to the datadir. As a challenge, the servers were part of a Galera Cluster.

Define preferred SST donor for Galera Cluster

oli.sennhauser@fromdual.com (Oli Sennhauser) — Fri, 15 Apr 2016 18:00:26 +0000

One of our customers recently ran into a problem, where he wanted to have a preferred donor for SST, whenever a node came up. The problem was, that the node did not come up, when the preferred donor was not running.

Galera Cache sizing

oli.sennhauser@fromdual.com (Oli Sennhauser) — Mon, 04 Apr 2016 22:03:38 +0000

To synchronize the data between the Galera Cluster and a new or re-entering Galera node Galera Cluster uses 2 different mechanisms:

FromDual Nagios and Icinga plugins v1.0.1 for MySQL/MariaDB released

oli.sennhauser@fromdual.com (Oli Sennhauser) — Tue, 23 Feb 2016 18:27:03 +0000

FromDual has the pleasure to announce the release of the new version 1.0.1 of the FromDual Nagios and Icinga plugins for MySQL, Galera Cluster and MariaDB.

MariaDB, Galera und MySQL training modules

oli.sennhauser@fromdual.com (Oli Sennhauser) — Tue, 29 Dec 2015 16:36:34 +0000

FromDual offers different MySQL, Galera Cluster and MariaDB training modules. For training dates see our MySQL and MariaDB training class schedule.

Nagios and Icinga plugins for MySQL/MariaDB released

oli.sennhauser@fromdual.com (Oli Sennhauser) — Wed, 04 Mar 2015 13:03:58 +0000

FromDual is pleased to announce the release of a new version 1.0.0 of the Nagios and Icinga plugins for MySQL, MariaDB, Percona Server and Galera Cluster.

Making HAProxy High Available for MySQL Galera Cluster

oli.sennhauser@fromdual.com (Oli Sennhauser) — Sun, 14 Dec 2014 18:37:50 +0000

After properly installing and testing a Galera Cluster we see that the set-up is not finished yet. It needs something in front of the Galera Cluster that balances the load over all nodes.
So we install a load balancer in front of the Galera Cluster. Typically nowadays HAProxy is chosen for this purpose. But then we find, that the whole Galera Cluster is still not high available in case the load balancer fails or dies. So we need a second load balancer for high availability.
But how should we properly failover when the HAProxy load balancer dies? For this purpose we put a Virtual IP (VIP) in front of the HAProxy load balancer pair. The Virtual IP is controlled and failovered with Keepalived.

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.