October 31, 2014 By Severalnines

When running a MariaDB Cluster or Percona XtraDB Cluster, it is common to use a load balancer to distribute client requests across multiple database nodes. Load balancing SQL requests aims to optimize the usage of the database nodes, maximize throughput, minimize response times and avoid overload of the Galera nodes. 

In this blog post, we’ll take a look at four different open source load balancers, and do a quick benchmark to compare performance:

• HAproxy by HAproxy Technologies
• IPVS by Linux Virtual Server Project
• Galera Load Balancer by Codership
• mysqlproxy by Oracle (alpha)

Note that there are other options out there, e.g. MaxScale from the MariaDB team, that we plan to cover in a future post.

…

In a few weeks I’m presenting “Performance Benchmarking: Tips, Tricks, and Lessons Learned” at Percona Live London 2014 (November 3-4). I continue to learn lessons and improve my benchmarking capabilities, so the content is a full upgrade from my presentation at Percona Live Santa Clara in April 2013. Anyone interested in achieving and sustaining the best performance out of their software/hardware/application should attend.

Also, Tokutek is sponsoring so we’ll be available in the expo hall throughout the show.

If you are attending or in the area and want to learn more about …

Normally, when we want to start PXC (Percona XtraDB Cluster) on RHEL/CentOS 6 or older then that, we can simply start with init.d script or service command. i.e

shell> /etc/init.d/mysql start 
OR 
shell> /etc/init.d/mysql bootstrap-pxc

shell> service mysql start.

But, the way is changed from CentOS 7. Because systemd integration with RHEL/CentOS 7 is now available for Percona XtraDB Cluster (#1342223).

So now, we have to start mysql with systemctl command i.e

shell> systemctl start mysql

For boostrap,

shell> systemctl start mysql@bootstrap.service

I would also suggest to read one very informative post by Przemek for recovering PXC cluster. …

September 18, 2014 By Severalnines

Galera Cluster is a popular choice for achieving high availability using synchronous replication. Though if you are planning to run huge sites with many DB objects (tables), a few tweaks are necessary. 

Yes, you might have been successful in loading your 1000s of databases and 1000s of tables, but what happens if you have a node failure and Galera recovery fails?

In this blog post we will show you how to determine one common error related to the open_files_limit that MySQL imposes, and also to spot another potential pitfall.

Open_files_limit

If you are using wsrep_sst_method=xtrabackup or wsrep_sst_method=xtrabackup-v2 then you will find a log file in the data directory of the donor node. This log file is called innobackup.backup.log.

140912 19:10:15  innobackupex: Done. …

September 10, 2014 By Severalnines

If you are automating your infrastructure using Puppet, then this blog is for you. We are glad to announce the availability of a Puppet module for ClusterControl. For those using Chef, we already published Chef cookbooks for Galera Cluster and ClusterControl some time back.  

ClusterControl on Puppet Forge

The ClusterControl module initial release is available on Puppet Forge, installing the module is as easy as:

$ puppet module install severalnines-clustercontrol

If you haven’t change the default module path, this module will be installed under /etc/puppet/modules/clustercontrol on …

September 9, 2014 By Severalnines

We are excited to announce the availability of YUM/APT repositories for ClusterControl, making new releases of ClusterControl  easily accessible using YUM or APT package managers. The repo is found at http://repo.severalnines.com, with instructions provided on the landing page. Our Cluster Configurators will be using these repositories. As a result, users upgrading from s9s_upgrade_cmon starting from version v.1.2.8 will be configured with the package repository.

ClusterControl requires extra post-installation setup steps, such as generating an API token, configuring cmon/dcps database schema, grant privileges on cmon schema, setting up SSL and so on. We provide a post-installation script for this purpose at [Apache document …

September 3, 2014 By Severalnines

Running your database cluster on AWS is a great way to adapt to changing workloads by adding/removing instances, or by scaling up/down each instance. At Severalnines, we talk much more about scale-out than scale up, but there are cases where you might want to scale up an instance instead of scaling out. 

In this post, we’ll show you how to change instance sizes with respect to RAM, CPU and IOPS, and how to tune your Galera nodes accordingly. Moreover, this post assumes that instances are launched using Amazon VPC.

When do we need to upgrade an instance?

You typically need to upgrade an instance when you run out of server resources. This includes CPU, RAM, storage capacity, disk throughput and bandwidth. You must allow enough headroom for …

September 1, 2014 By Severalnines

According to Forrester, a DBA in a large enterprise manages between 8 and 275 databases, with the industry average being 40 databases to a DBA. Larger databases usually require extra effort around tuning, backup, recovery and upgrade. Cloud, as well as automation and management tools can help improve the number of databases managed by one DBA.  

With that background, we were pretty excited to introduce support for management of single-instance MySQL and MariaDB databases in ClusterControl 1.2.6. The majority, if not all of the cluster users out there, use single-instance or master-slave replicated setups along their mission-critical …

Covering indexes can result in orders of magnitude performance improvements for queries. Bradley’s presentation on covering indexes describes what a covering index is, how it can effect performance, and why it works. However, the definition of a covering index can get cumbersome since MySQL limits the number of columns in a key to 16 (32 on MariaDB).

Tokutek introduced multiple clustering indexes into MySQL to address these problems. Zardosht describes the multiple clustering indexes feature and how clustering indexes differ from covering indexes. Zardosht also describes the …

August 6, 2014 By Severalnines

Well over a thousand sessions have been submitted for the OpenStack Summit and two of them includes our good selves! We’ve submitted two talks with partners of ours: 

• ClusterControl: Efficient and reliable MySQL Management, Monitoring, and Troubleshooting for OpenStack HA)
• Deploying Databases for OpenStack

… and would love it if the talks were included in the final agenda. For that to happen, we need a few more of your votes today!

The OpenStack Summit is a five-day conference for developers, users, and …