Percona XtraDB Cluster (PXC) is different enough from async replication that it can be a bit of a puzzle how to do things the Galera way.  This post will attempt to illustrate the basics of setting up 2 node PXC cluster from scratch.

Requirements

Two servers (could be VMs) that can talk to each other.  I’m using CentOS for this post.  Here’s a dirt-simple Vagrant setup: https://github.com/jayjanssen/two_centos_nodes to make this easy (on Virtualbox).

These servers are talking over the 192.168.70.0/24 internal network for our example.

jayj@~/Src $ git clone https://github.com/jayjanssen/two_centos_nodes.git
jayj@~/Src $ cd two_centos_nodes
jayj@~/Src/two_centos_nodes $ vagrant up
 Bringing machine 'node1' up …

The aim of this post is to enumerate real-world usage of Percona XtraDB Cluster (PXC), and also to solicit use cases from the readers. One of the prominent usages in the production environment that we have come across (and our Percona consultants have assisted) is that of HP Cloud. There is a post about it here by Patrick Galbraith of HP. The post focuses on their deployment of PXC for HP Cloud DNS. The post focuses on the key aspects of synchronous replication setup with high-availability guarantees like split-brain immunity.

Nobody likes to debug async replication while its broken or …

Selecting the most appropriate solution for a MySQL HA infrastructure is as much a business and philosophical decision as it is a technical one, but often the choice is made without adequately considering all three perspectives.  When too much attention is paid to one of these aspects at the cost of the others, the resulting system may be over-engineered, poorly-performing, and/or various other flavors of suboptimal.

On Wednesday, June 5, at 10 a.m. PDT (1700 UTC), I will be presenting a webinar entitled, Choosing a MySQL HA Solution, in which we’ll explore the topic of MySQL HA from each of these perspectives.  The goal will be to motivate your thinking about HA in a holistic fashion and help …

I talk with lot of people who are really interested in Percona XtraDB Cluster (PXC) and mostly they are interested in PXC as a high-availability solution.  But, what they tend not to think too much about is if moving from async to synchronous replication is right for their application or not.

Facts about Galera replication

There’s a lot of different facts about Galera that come into play here, and it isn’t always obvious how they will affect your database workload.  For example:

• Transaction commit takes approximately the worst packet round trip time (RTT) between any two nodes in your cluster.
• Transaction apply on slave nodes is still asynchronous from client commit (except on the original node where the transaction is committed)
• Galera prevents writing conflicts to these pending transactions …

Galera/Percona XtraDB Cluster (PXC) for MySQL is a hot thing right now and some users jump right in without enough testing. Consequently, they’re more likely to either suffer failure or issues that prevent them from moving forward. If you are thinking of migrating your workload to Percona XtraDB Cluster, make sure to go through these basics.

log_slave_updates is REQUIRED

You need to have log_slave_updates enabled on the cluster node acting as async slave for replicated events from the async master to be applied to the other nodes, that is if you have more than one PXC node. This is because before Galera can create writesets for the replicated events, binlog events must be generated for the transactions first. Under …

Percona Toolkit 2.1.8

Percona Toolkit 2.1.8 was released today and the new version comes with some pretty cool news: Beta support for MySQL 5.6 (which as you might know is also in beta).

In addition to various bug fixes, Percona Toolkit 2.1.8 also offers beta support for Percona XtraDB Cluster (PXC). Version 2.1.8 continues the trend of solid bug fix releases, and all 2.1 users are encouraged to upgrade.

You can download Percona Toolkit 2.1.8 here.  (More info on Percona Toolkit). Users who plan on running the tools on Percona XtraDB Cluster or MySQL 5.6 are advised to upgrade. …

Hot backups are important for high availability, they can run without blocking the application. Percona Xtrabackup is a great tool for backing up InnoDB data. 
We have created a backup tool called s9s_backup that makes Xtrabackup really easy to use, and is fully integrated with ClusterControl, which means that you can schedule backups with ease and view the backups that you have taken, and also restore the backups with no pain.

s9s_backup is available in the lastest version of ClusterControl or you can download it here.

Is mysqldump totally useless then?

No. If you would like to isolate and load only one table, mysqldump is great, or if you want to …

Blogging is the way to express an idea in an informal way by a person, who has either worked with it, or planning to work with it, or has seen it at work. In databases, ideas are the foundations of everything, and these Log Buffer Edition is presenting ideas from bloggers in Log Buffer #282. [...]

This post is a step-by-step guide to set up Percona XtraDB Cluster (PXC) in a virtualized test sandbox. I used Amazon EC2 micro instances, but the content here is applicable for any kind of virtualization technology (for example VirtualBox). The goal is to give step by step instructions, so the setup process is understandable and it could serve as a reference architecture.

You will need 4 virtual machines. 3 for PXC and 1 for the client, which will have HaProxy. I used CentOS 6 as the operating system, the instructions are similar for any Linux distribution.

The client node will have HaProxy installed and it will redirect requests to PXC nodes. This approach works well in real-world scenarios too. Running HaProxy on the application servers instead of having them as dedicated entities gives you benefits like you don’t need an extra network roundtrip because of a loadbalancer and scalability of PXC’s load balancing layer scales …

I have a customer who is considering Percona XtraDB Cluster (PXC) in a two colo WAN environment.  They wanted me to do a test comparing PXC against semi-synchronous replication to see how they stack up against each other.

Test Environment

The test environment included AWS EC2 nodes in US-East and US-West (Oregon).  The ping RTT latency between these nodes was right around 100ms.

All environments used Percona Server or Percona XtraDB Cluster server 5.5.24.  Innodb durability was disabled for all tests (innodb_flush_log_at_trx_commit=2).  All other settings were the same kept the same unless otherwise noted.

I tested against the following setups:

Control

The control …