February 4, 2015 By Severalnines Check Out Our Latest Technical Resources for MySQL, MariaDB & MongoDB Clusters

Like every month, we have created new content and tools for you; here is a summary of what we’ve published. Please do check it out and let us know if you have any comments or feedback.

New Live Technical Webinars

A DevOps Guide to Database Infrastructure Automation for eCommerce

Tuesday, February 17th

Infrastructure automation isn’t easy, but it’s not rocket science either, says Riaan Nolan. Automation is a worthwhile investment for retailers serious about eCommerce, but deciding on which …

January 30, 2015 By Severalnines

Thanks to everyone who participated in these two sessions this week! Please see below for details on next week’s follow up session 'Performance Tuning for HAProxy & MySQL'.

The topics covered this week included: 

• What is HAProxy?
• SQL Load balancing for MySQL
• Failure detection using MySQL health checks
• High Availability with Keepalived and Virtual IP
• Use cases: MySQL/MariaDB Galera Cluster, MySQL NDB …

Check Out Our Latest Technical Resources for MySQL, MariaDB & MongoDB Clusters

Like every month this year, we have created new content and tools for you; here is a summary of what we’ve published this December. Please do check it out and let us know if you have any comments or feedback.

And thank you for following us in the past 12 months and for your fidelity; we look forward to “seeing” you next year as well and wish you a great start to 2015!

New Live Technical Webinars

Infrastructure automation isn’t easy, but it’s not rocket science either, says Riaan Nolan. Riaan has been in operations for the past decade, and has built over a dozen eCommerce …

HAProxy is frequently used as a software load balancer in the MySQL world. Peter Boros, in a past post, explained how to set it up with Percona XtraDB Cluster (PXC) so that it only sends queries to available nodes. The same approach can be used in a regular master-slaves setup to spread the read load across multiple slaves. However with MySQL replication, another factor comes into play: replication lag. In this case the approach mentioned for Percona XtraDB Cluster does not work that well as the check we presented only returns ‘up’ or ‘down’. We would like to be able to tune the weight of a replica inside HAProxy depending on its replication lag. This is what we will do in this post using HAProxy 1.5.

Agent …

HAProxy is frequently used as a load-balancer in front of a Galera cluster. While diagnosing an issue with HAProxy configuration, I realized that logging doesn’t work out of the box on CentOS 6.5. Here is a simple recipe to fix the issue.

If you look at the top of /etc/haproxy/haproxy.cfg, you will see something like:

global
    log         127.0.0.1 local2
[...]

This means that HAProxy will send its messages to rsyslog on 127.0.0.1. But by default, rsyslog doesn’t listen on any address, hence the issue.

Let’s edit /etc/rsyslog.conf and uncomment these lines:

$ModLoad imudp
$UDPServerRun 514

This will make rsyslog listen on UDP port 514 for all IP addresses. Optionally you can limit to 127.0.0.1 by adding:

$UDPServerAddress …

September 11, 2014 By Severalnines

Thanks to everyone who attended and participated in this week’s webinar on ‘Performance Tuning of HAProxy for Database Load Balancing’. And special thanks to our guest speaker, Baptiste Assmann of HAProxy Technologies. 

If you missed the sessions or would like to watch the webinar again & browse through the slides, they are now available online.

Watch the replay of this webinar to learn about what HAProxy can tell you about your application and database instances. And understand the difference between short-lived connections and persistent connections, and how they affect the performance and availability of your applications. 

Watch the replay Performance …

August 28, 2014 By Severalnines Check Out Our Latest Resources for MySQL, MariaDB & MongoDB Clusters

Here is a summary of resources & tools that we’ve made available to you in the past weeks. If you have any questions on these, feel free to contact us!

New Technical Webinars

Performance Tuning of HAProxy for Database Load Balancing

09 September 2014 - with Baptiste Assmann of HAProxy Technologies

Do you know what HAProxy can tell you about your application and database instances? Do you know the difference …

August 13, 2014 By Severalnines

New Webinar: Performance Tuning of HAProxy for Database Load Balancing

Date, Time & Registration: 

Tuesday, September 9th @10am CEST (Europe & MEA / Asia Pacific)

Register here

Tuesday, …

June 17, 2014 By Severalnines

We continuously see great interest in MySQL load balancing and HAProxy, so we thought it was about time we organised a live webinar on the topic!

As most of your will know, database clusters and load balancing go hand in hand. 

Once your data is distributed and replicated across multiple database nodes, a load balancing mechanism helps distribute database requests, and gives applications a single database endpoint to connect to. 

Instance failures or maintenance operations like node additions/removals, reconfigurations or version upgrades can be masked behind a load balancer. This provides an efficient way of isolating changes in the database layer from the rest of the …

December 19, 2013 By Severalnines

Database clusters are pretty sophisticated distributed systems with complex dependencies between nodes. The failure of a node will generally impact the overall cluster, as the remaining nodes need to reconfigure themselves to continue to operate without the failed node. Since re-introducing a node will also affect the existing cluster, the timing could therefore be dependent on the state of the other nodes in the cluster. Repair and restarts often needs to be performed in a particular order in compliance with the redundancy model of the cluster so as not to jeopardize the normal functioning of existing nodes.

Webinar: Repair and Recovery for your MySQL, MariaDB and MongoDB/TokuMX clusters

…