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89 blog posts in 13 categories

Point-in-time Recovery in MySQL Galera Cluster

Data protection is vital for DB admins, especially when it involves data that is accessed and updated 24 hours a day. Clustering and replication are techniques that provide protection against failures, but what if a user or DBA issues a detrimental command against one of the databases? A user might erroneously delete or update the contents of one or more tables, drop database objects that are still needed during an update to an application, or run a large batch update that fails midway. How do we recover lost data?

Understanding gcache in Galera

Galera uses a preallocated file with a specific size called gcache, used to store the writesets in circular buffer style. By default, its size is 128MB. In this post, we are going to explore how to leverage gcache to improve the operation of a Galera cluster.

Avoiding Deadlocks in Galera - Set up HAProxy for single-node writes and multi-node reads

Galera cluster has known limitations, one of them is that it uses cluster-wide optimistic locking. This may cause some transactions to rollback. With an increasing number of writeable masters, the transaction rollback rate may increase, especially if there is write contention on the same dataset. It is of course possible to retry the transaction and perhaps it will COMMIT in the retries, but this will add to the transaction latency. However, some designs are deadlock prone, e.g sequence tables. In this blog we present how you can minimize the risk for deadlocks due to the design of Galera. 

From the Field - Live Migration from MMM to MariaDB Galera Cluster

This is a guest post from Igor Shevtsov, a MySQL DBA based in Twickenham, UK. Igor has had the opportunity to deploy and manage different types of high availability MySQL solutions, and we invited him to share his experience. Igor can be contacted by email or LinkedIn.

Migrating MySQL Galera Cluster to a new Data Center without Downtime

Are you tired and frustrated with your hosting or cloud provider? Have you seen a constant degradation in service levels and responsiveness? Or was the public cloud a bit too expensive after all, and you’re ready to move everything to in-house servers? Welcome to the club. Data migrations are painful and scary. Running a migration with scheduled downtime is hard enough as it is, but for certain applications, a prolonged period of downtime is not acceptable. Without the right strategy, a migration might leave you with inconsistent or lost data, hours of downtime and a negative impact to your business. This is why it is so hard to switch hosting or cloud providers. Once your data is in somebody else’s infrastructure, they’ve got you by the balls.

How to Clone Your Database

If you are managing a production database, chances are high that you’ve had to clone your database to a different server than the production server. The basic method of creating a clone is to restore a database from a recent backup on to a different database server. Other methods include replicating from a source database while it is up, in which case it is important the original database be unaffected by any cloning procedure.

Replicate from a MySQL Server into a Galera Cluster

This article describes how to setup replication between a regular MySQL server and a Galera Cluster.

Scaling Wordpress and MySQL on Multiple Servers for Performance

Over the years, WordPress has evolved from a simple blogging platform to a CMS. Over seven million sites use it today, including the likes of CNN, Forbes, The New York Times and eBay. So, how do you scale Wordpress on multiple servers for high performance? 

Scaling Drupal on Multiple Servers with Galera Cluster for MySQL

This post shows you how to move from a single instance Drupal/MySQL to a multi-server environment. A well designed multi-server deployment not only allows Drupal to scale, but will also enhance redundancy by removing single points of failure. Components used are Apache, PHP, csync2, lsyncd, Keepalived, HAproxy,&MySQL Galera ClusterClusterControl.