failover

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.

FromDual has the pleasure to announce the release of the new version 0.9.2 of its popular FromDual Ops Center for MariaDB and MySQL focmm.

The FromDual Ops Center for MariaDB and MySQL (focmm) helps DBA's and System Administrators to manage MariaDB and MySQL database farms. Ops Center makes DBA and Admins life easier!

FromDual has the pleasure to announce the release of the new version 0.9.1 of its popular FromDual Ops Center for MariaDB and MySQL focmm.

The FromDual Ops Center for MariaDB and MySQL (focmm) helps DBA's and System Administrators to manage MariaDB and MySQL database farms. Ops Center makes DBA and Admins life easier!

Caution: We have introduced an evil bug which prohibits installation of focmm. Sorry! Somehow it did pass our QA. To fix this bug update file lib/Upgrade.inc on Line 1965 as follows:

- $sql = sprintf("REPLACE INTO `focmm_configuration` (`key`, `value`) VALUES ('%s', '%s'), ('%s', '%s'), ('%s', '%s')"
+ $sql = sprintf("REPLACE INTO `focmm_configuration` (`key`, `value`) VALUES ('%s', '%s'), ('%s', '%s')"

In the meanwhile we prepare a new release.

FromDual has the pleasure to announce the release of the new version 0.3 of the FromDual Ops Center for MySQL and MariaDB.

The FromDual Ops Center for MySQL and MariaDB (focmm) is an application for DBA's and system administrators to manage MySQL and MariaDB database farms.

The main task of Ops Center is to support you in your daily MySQL and MariaDB operation tasks.

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:

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:

In the following article I have summarized some steps and hints to set-up a MySQL active/passive failover Cluster also sometimes called MySQL HA.

With such a set-up you can achieve a 99.99% (4x9) HA set-up for MySQL (52 minutes downtime per year). The same procedure also works for PostgreSQL, Oracle and other database systems running on Linux (DRBD runs on Linux only).

The concept

The concept of an active/passive failover Cluster is the following:

Vor ein paar Tagen hatte ich wieder einmal mit einer MySQL Cluster Replikation zu tun. Ich habe das schon eine Weile nicht mehr angelangt und war somit vorbereitet, wieder einmal ein paar Überraschungen zu erleben.

Diejenige, für welche MySQL Cluster - Cluster Ring-Replikationen das tägliche Brot ist, können diesen Artikel getrost überspringen. Alle anderen können möglicherweise von unseren Erfahrungen profitieren.

Wir hatten das folgende MySQL Cluster Konstrukt im Einsatz:

A few days ago I had to deal with MySQL Cluster replication. I did not do this for a while so I was prepared to expect some interesting surprises once again.

For those who MySQL Cluster - Cluster circular replication is the daily business they may skip this article. For all the others they possibly can profit from our learnings.

I am talking about the following MySQL Cluster set-up:

Electing a slave as new master and aligning the other slaves to the new master

In a simple MySQL Replication set-up you have high-availability (HA) on the read side (r). But for the master which covers all the writes (w) and the time critical read (rt) there is no HA implemented. For some situations this can be OK. For example if you have rarely writes or if you can wait until a new Master is set up.

But in other cases you need a fast failover to a new master.