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Displaying posts with tag: topology (reset)
MySQL replication in action - Part 4 - star and hybrid topologies

Previous episodes:

MySQL replication in action - Part 1: GTID & CoMySQL replication in action - Part 2 - Fan-in topologyMySQL replication in action - Part 3 - All-masters P2P topology
Introducing star topology.In all-masters P2P topologies, we have seen that we have a way of deploying a topology where all nodes are masters, and achieve better efficiency and stability than ring topologies. That …

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MySQL replication in action - Part 3: all-masters P2P topology

Previous episodes:

MySQL replication in action - Part 1: GTID & CoMySQL replication in action - Part 2 - Fan-in topology


In the previous article, we saw the basics of establishing replication from multiple origins to the same destination. By extending that concept, we can deploy more complex topologies, such as the point-to-point (P2P) all-masters topology, a robust and …

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MySQL replication in action - Part 2 - Fan-in topology


Introduction: where we standPrevious episodes:

MySQL replication in action - Part 1: GTID & Co
In the latest releases of MySQL and MariaDB we have seen several replication improvements. One of the most exciting additions is the ability to enhance basic replication with multiple sources. Those who have used replication for a while should remember that one of the tenets of the “old” replication was that a slave couldn’t have more than one master. This was The Law and there was no escape ... until now. The only way to work around that prohibition was to use circular replication, also known …

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tpm, the multi-master composer

Multi master topologies blues

Tungsten Replicator is a powerful replication engine that, in addition to providing the same features as MySQL Replication, can also create several topologies, such as

  • all-masters: every master in the deployment is a master, and all nodes are connected point-to-point, so that there is no single point of failure (SPOF).
  • fan-in: Several masters can replicate into a single slave;
  • star: It’s an all-masters topology, where one node acts as hub which simplifies the deployment at the price of creating a SPOF.

The real weakness of these topologies is that they don’t come together easily. Installation requires several commands, and running them unassisted is a daunting task. Some time ago, we introduced a set of scripts (the Tungsten Cookbook) that allow you to install multi-master topologies with a …

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Installing and administering Tungsten Replicator - Part 2 : advanced

Switching roles

To get a taste of the power of Tungsten Replicator, we will show how to switch roles. This is a controlled operation (as opposed to fail-over), where we can decide when to switch and which nodes are involved.

In our topology, host1 is the master, and we have three slaves. We can either ask for a switch and let the script select the first available slave, or tell the script which slave should be promoted. The script will show us the steps needed to perform the operation.

IMPORTANT! Please note that this operation is not risk free. Tungsten replicator is a simple replication system, not a complete management tool like Continuent Tungsten. WIth the replicator, you must make sure that the applications have stopped writing to the master before starting the switch, and then you should address the application to the new master when the …

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Installing and Administering Tungsten Replicator - Part 1 - basics

Intro

Tungsten Replicator is an open source tool that does high performance replication across database servers. It was designed to replace MySQL replication, although it also supports replication from and to Oracle and other systems. In this article, we will only cover MySQL replication, both simple and multi-master.

Preparing for installation

To follow the material in this article, you will need a recent build of Tungsten Replicator. You can get the latest ones from http://bit.ly/tr20_builds. In this article, we are using build 2.0.8-167.

Before starting any installation, you should make sure that you have satisfied all the prerequisites. Don't underestimate the list. Any missing …

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Multi-master data conflicts - Part 2: dealing with conflicts

In the first part of this article we examined the types of conflicts and their causes. In this part, we will analyse some of the methods available to deal with conflicts.

Pessimistic locking (or: conflicts won't happen)

Applicability: synchronous clusters with 2pc

We've covered this topic in the previous article, but it's worth repeating. If you use a synchronous cluster, you don't have conflicts. For example, MySQL Cluster ensures consistent data with updates coming from different nodes. However, MySQL Cluster is not a replacement for a MySQL server, and it has severe limitations.


Optimistic locking

Applicability: synchronous clusters without 2pc (Galera)

Conflicting transactions proceed on different nodes with local locking. The last one then …

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Tungsten Replicator 2.0.7 is released

Tungsten Replicator 2.0.7 was released today. In addition to a large number of bug fixes, this release adds several improvements for multi-master management, and support for Amazon RDS (as a slave).

While the Release Notes show a long list of improvements, I would like to focus on some of them that improve the handling of multi-master deployments.

When we released version 2.0.6, we added the first revision of the cookbook recipes in the build. That was still a green addition, which caused several bug reports. But since then, we have integrated the cookbook in our internal testing, making these recipes more robust and reliable. We are also planning to improve them and eventually …

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Solving replication problems with Tungsten replicator

On Monday afternoon, Neal Armitage and I will be speaking at Percona Live in London. It will be a three hours tutorial about Tungsten replicator.

The contents of this tutorial are mostly new. We have released recently a new and easier way of installing different topologies, in the shape of cookbook scripts, which are distributed with the replicator tarball.

Using this cookbook, any user can simply install multiple topologies, from the simple master/slave to all-masters, fan-in, and star.

There are recipes for showing the replication cluster, switching roles between master and a chosen slave, taking over MySQL replication, installing direct slaves with parallel replication, testing each topology, and uninstalling all.

All the above will be demonstrated during the tutorial, with the addition of conflict prevention and more management …

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Chaining Replication Clusters

MySQL built-in replication includes a concept called relay slave, which allows you to create hierarchical database clusters. You can do the same thing with Tungsten, and this can be done in more than one way. Let's start with two distinct clusters. We can follow the recipes in the Tungsten Cookbook to install a master / slave cluster in three separate hosts and a …

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