In this three-part blog series, we introduced a High Availability (HA) Framework for MySQL hosting in Part I, and discussed the details of MySQL semisynchronous replication in Part II. Now in Part III, we review how the framework handles some of the important MySQL failure scenarios and recovers to ensure high availability.

MySQL Failure Scenarios Scenario 1 – Master MySQL Goes Down

• The Corosync and Pacemaker framework detects that the master MySQL is no longer available. Pacemaker demotes the master resource and tries …

In this three-part blog series, we will explain the details and functionality of a High Availability (HA) framework for MySQL hosting using MySQL semisynchronous replication and the Corosync plus Pacemaker stack. In Part I, we’ll walk you through the basics of High Availability, the components of an HA framework, and then introduce you to the HA framework for MySQL.

What is High Availability?

The availability of a computer system is the percentage of time its services are up during a period of time. It’s generally expressed as a series of 9′s. For example, the table below shows availability and the corresponding downtime measured over one year.

Recently I’ve had to rename a node on a production cluster – however, I did not have an experience on this yet so I decided to try on a sandbox and establish a known procedure. Without further ado, assuming we have 3 nodes and we want to rename ha3’s hostname to ha03.

[root@ha01 ~]# crm status
Last updated: Wed Jun  4 21:55:01 2014
Last change: Wed Jun  4 21:53:35 2014 via crm_attribute on ha01.localdomain
Stack: classic openais (with plugin)
Current DC: ha01.localdomain - partition with quorum
Version: 1.1.10-14.el6_5.2-368c726
3 Nodes configured, 3 expected votes
6 Resources configured


Online: [ ha01.localdomain ha02.localdomain ha3.localdomain ]

 Master/Slave Set: ms_MySQL [p_mysql]
     Masters: [ ha01.localdomain ]
     Slaves: [ ha02.localdomain ha3.localdomain ]
 Clone Set: ping_gw_clone [ping_gw]
     Started: [ ha01.localdomain ha02.localdomain ha3.localdomain ]

Here we go:

1. Put ha3 on standby:

   [root@ha01 ~]# …

I’m speaking at Percona Live, LinuxCon Europe, and linux.conf.au. And I just co-founded a new company.

I have a few busy weeks behind me, and even busier weeks ahead. If you’ve been wondering why recently I haven’t been updating this space too frequently, here’s why:

Yours truly and fellow ex-Linbiters Martin Loschwitz and Andreas Kurz have recently founded hastexo, an independent professional services organization focused on open-source high availability and disaster recovery. We are already offering both on-site and …

This year’s Linux Plumbers Conference is taking place November 3-5, in Cambridge, MA, United States. The CfP is already closed and the program is due any day now, but the co-located miniconference on high availability clustering is still accepting proposals. This is your chance to get involved!

So if you plan to attend Plumbers or just happen to be in the area, please submit your talk! Miniconference talks are not expected to be full-blown presentations. Instead, you can float an …

The full Linux cluster stack, including Pacemaker, Heartbeat, Corosync and related packages, cleared all hurdles and migrated to the Debian testing repository this morning. This means that Pacemaker and both messaging layers it supports will be in the upcoming Debian release, codenamed squeeze.

Credit goes to the debian-ha maintainers crowd for making this possible: Martin Loschwitz, …