Overview

Clustering provides high availability and disaster recovery, along with the ability to read-scale both locally and globally. Some clusters even provide active/active capabilities, which others have a single master.

Real time database replication is a must for clustering and other key business purposes, like reporting. There are a number of replication technologies available for MySQL, and some are even bundled into various solutions. When choosing a replication methodology, it is paramount to understand just how the data moves from source to target. In this blog post, we will examine how asynchronous, synchronous, and “semi-synchronous” replication behave when used for clustering. Also, we will explore how …

Just about a month ago, Pavel Ivanov released Ripple under the Apache-2.0 license. Ripple is a MySQL binlog server: software which receives binary logs from MySQL or MariaDB servers and delivers them to another MySQL or MariaDB server. Practically ,this is an intermediary master which does not store any data, except the binary logs themselves, and does not apply events. This solution allows saving of a lot of resources on the server, which acts only as a middle-man between the master and its actual slave(s).

The intermediary server, keeping binary logs only and not doing any other job, is a prevalent use case which allows us to remove IO (binlog read) and network (binlog retrieval via network) load from the actual …

In Part I, we introduced a High Availability (HA) framework for MySQL hosting and discussed various components and their functionality. Now in Part II, we will discuss the details of MySQL semisynchronous replication and the related configuration settings that help us ensure redundancy and consistency of the data in our HA setup. Make sure to check back in for Part III where we will review various failure scenarios that could arise and the way the framework responds and recovers from these conditions.

What is MySQL Semisynchronous Replication?

Simply put, in a …

This blog post explains benefits, features and limitations of the improved semi-sync replication in MySQL 5.7

The post Improved Semi-Sync Replication in MySQL 5.7 appeared first on Datavail.

Async and PXC

A common question I get about Percona XtraDB Cluster is if you can mix it with asynchronous replication, and the answer is yes!  You can pick any node in your cluster and it can either be either a slave or a master just like any other regular MySQL standalone server (Just be sure to use log-slave-updates in both cases on the node in question!).  Consider this architecture:

However, there are some caveats to be aware of.  If you slave from a cluster node, there is no built in mechanism to fail that slave over automatically to another master node in your cluster.  You cannot assume that the binary log positions are the same on all nodes in your cluster (even if they start binary logging at the same time), so you can’t issue a CHANGE MASTER without knowing the proper binary log position to start at.

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