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Ansible and Loading MySQL Databases Part II

Loading databases on virtual systems is not as straight forward as it should be. Last time the foundation for using Ansible was set down on our quest to be able to have fully functional database servers on virtual servers automatically. But that prompted a few of you to remind me that you do not always need Ansible.

Without Ansible
You can have Vagrant do the work. Modify the vagrant file to run a script to run a script when provisioned, such as
config.vm.provision :shell,path: "setup.sh"
and create the setup.sh shell script.

#!/bin/bash
#
# example setup script for LAMP stack on Vagant box
sudo apt-get -y update
sudo apt-get -y install apache2 php5 libapache2-mod-php5
## Set …
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Monitoring High Availability on Galera Clusters for MySQL using MONyog

For every online business, there are millions of transactions happening every second including crucial revenue bearing transactions. Therefore downtime, both planned and unplanned has a cost attached to it and results in lost revenue every second. As the technology improved to meet this demand, the importance of High Availability (HA) became the focus point.

The introduction of Galera Cluster for MySQL bought true Multimaster Cluster thanks to its synchronous replication. In this article, we’ll show how using MONyog in tandem with Galera provides a simple and best-in-class High Availability solution for MySQL users.

How to register a Galera Cluster Node in MONyog

  1. Enter the Hostname, port and credentials in “MySQL settings”, test the connection and save it.
  2. Enable “Galera” group from “Customize” > “Manage monitor groups”
  3. In Monitors page, select the “Galera” group and …
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New! MySQL Connector/Arduino release-1.0.4 GA and Documentation

After several iterations and a long period of community evaluation, I am happy to report I've released the newest, stable release of the MySQL Connector/Arduino. This library is designed to allow you to connect your Arduino via an Ethernet or WiFi shield to a MySQL database server running on your network (or the Internet!).

New Documentation! Best of all, I've written a reference manual that includes examples of how to use the connector in a variety of ways. Included in the document are advice on how to write your sketches, troubleshooting tips, and a long FAQ compiled from the many questions from my blogs.

Changes The only code change in this release is to fix a defect when using the connector with the latest versions of MySQL.

Downloading the Connector To download the connector library and the new reference manual, visit …

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MySQL in a USB, with a little help of Fabric

If you’ve wanted to see how well MySQL Fabric actually works and how easy it makes setting up replication and switching Masters & Slaves back and forth, with a sample use case of having the master stored in a USB stick, then feel free to have a look at:

http://www.slideshare.net/keithhollman5/mysql-fabric-in-a-usb

o la versión en Español:

http://www.slideshare.net/keithhollman5/mysql-fabric-en-un-usb

Please let me know what you think.

New Optimizer Hints in MySQL

The MySQL optimizer has a well known special system variable—optimizer_switch—which allows control of various optimizer modes such as index condition pushdown (ICP), batched key access, etc. One big disadvantage of using the optimizer_switch, however, is that changing its value is an extra step in the query execution.…

Can’t Be Any Faster Than That: A Real-Life Experiment with Latency in a Geo-distributed Environment

Introduction

A question frequently asked is how much latency does Galera have in geo-distributed environments. After all, snail mail can also be used for database replication, but the latency will not be acceptable.

Let’s see how Galera performs.

A Two-Datacenter Setup

We start by creating a two-node cluster using a pair of Amazon EC2 regions that are as far apart Internet-wise as it gets – Sydney and São Paulo. The underwater cable maps do not show a direct link between Australia and South America.

The ICMP round-trip time between the two regions is a steady 316 ms:


root@ip-172-31-4-77:/home/ubuntu# ping ec2-54-94-217-199.sa-east-1.compute.amazonaws.com
PING ec2-54-94-217-199.sa-east-1.compute.amazonaws.com (54.94.217.199) 56(84) bytes of data.
64 bytes from ec2-54-94-217-199.sa-east-1.compute.amazonaws.com …
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Getting SIGABRT -> Assertion `is_binlog_empty()’ failed with MySQL 5.7.7-rc

What about inserting data to MySQL 5.7.7-rc-debug with GTID/binary log enabled. It is OK until you hit disk full condition while inserting data. It will crash on the way and likely you will lose MySQL. Error log indicates related problem:

2015-07-29T07:20:05.865708Z 2 [ERROR] InnoDB: posix_fallocate(): Failed to preallocate data for file ./sls2/sales.ibd, desired size 4194304 bytes. Operating system error number 28. Check that the disk is not full or a disk quota exceeded. Make sure the file system supports this function. Some operating system error numbers are described at http://dev.mysql.com/doc/refman/5.7/en/operating-system-error-codes.html
2015-07-29T07:20:05.895529Z 2 [Warning] InnoDB: 1048576 bytes should have been written. Only 557056 bytes written. Retrying again to write the remaining bytes.
2015-07-29T07:20:05.905149Z 2 [Warning] InnoDB: 491520 bytes should have been written. Only 106496 bytes written. Retrying again to write the remaining …
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Securing your MySQL server

After installing a MySQL database server, like the one I posted earlier, if it's going to be a production environment than you should consider securing the instance by eliminating some of the basic vulnerabilities that come with a generic install. Fortunately MySQL and MariaDB already come with a tool for that purpose, called mysql_secure_installation. This program enables to perform the

Multi-source replication in MySQL 5.7 vs Tungsten Replicator

MySQL 5.7 comes with a new set of features and multi-source replication is one of them. In few words this means that one slave can replicate from different masters simultaneously.

During the last couple of months I’ve been playing a lot with this trying to analyze its potential in a real case that I’ve been facing while working with a customer.

This was motivated because my customer is already using multi-sourced slaves with Tungsten Replicator and I wanted to do a side-by-side comparison between Tungsten Replicator and Multi-source Replication in MySQL 5.7

Consider the following scenario:


DB1 is our main master attending mostly writes from several applications, it also needs to serve read …

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About the new warnings generated during 'PURGE BINARY LOGS' execution

In this blog, I will discuss about warnings that users might face if they are trying to purge active/in_use binary log which are introduced in MySQL-5.6.12/MySQL-5.7.2 releases.  Before jumping directly to that, I will be covering few basic things about PURGE BINARY LOGS command, about safe way to purge the binary logs on a replication forum. If you are good at basics on "PURGE BINARY LOGS" , you can choose to directly move to the section (at the end of the blog) where I was talking about these new warnings.

Introduction:
==========
A binary log file contains “events” that describe database changes occurred on a MySQL Server (typically called Master) that enabled binary logging using --log-bin. On a Master server, the files that are related to binary logging are binary log files (files with binlog_base_name.6_digit serial_number) and a binary log index file (file with …

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