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Tweaking MySQL Galera Cluster to Handle Large Databases - open_files_limit

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.

Webinar Replay: Performance Tuning of HAProxy for Database Load Balancing

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.

How to Change AWS Instance Sizes for Your Galera Cluster and Optimize Performance

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. 

Clustering Moodle on Multiple Servers for High Availability and Scalability

Moodle is an open-source e-learning platform (aka Learning Management System) that is widely adopted by educational institutions to create and administer online courses. For larger student bodies and higher volumes of instruction, moodle must be robust enough to serve thousands of learners, administrators, content builders and instructors simultaneously. Availability and scalability are key requirements as moodle becomes a critical application for course providers. In this blog, we will show you how to deploy and cluster moodle/web, database and file-system components on multiple servers to achieve both high availability and scalability. 

How-To and Performance Impacts of SSL-Encrypted Replication Traffic in Galera Cluster for MySQL

Deploying Galera Clusters across WAN environments might lead to concerns around data privacy and security - especially as more organisations are having to comply with national and international regulations. You would not want hackers eavesdropping or intercepting replication traffic. Encrypted replication hides what is sent between the Galera nodes, and makes sure each node is only communicating to the ones it trusts. But how expensive is encryption?

Webinar Replay: How To Set Up SQL Load Balancing with HAProxy

Thanks to everyone who attended and participated in last week’s webinar on ‘How To Set Up SQL Load Balancing With HAProxy’!

Clustering SugarCRM with MySQL Galera for High Availability and Performance

SugarCRM is the leader in open source CRM systems, and has been adopted by some of the largest firms, including IBM. The CRM software includes all sales, marketing and support tools out of the box, and can also be extended to integrate social media sources. For those depending on SugarCRM, especially when deploying in cloud environments with lower SLAs, having a high availability architecture can make a lot of sense. 

How to Cluster Liferay with MySQL Galera and Ceph for High Availability and Performance

Liferay is an open-source content management system written in Java. It is used by a number of high traffic sites, as this survey suggests. 

Online Schema Upgrade in MySQL Galera Cluster using TOI Method

As a follow-up to the Webinar on Zero Downtime Schema Changes in Galera Cluster, we’ll now walk you through the detailed steps on how to update your schema. The two methods (TOI and RSU) have both their pros and cons, and given parameters like table size, indexes, key_buffer_size, disk speed, etc., it is possible to estimate the time taken for the schema to be upgraded.

Avoiding Deadlocks in Galera - Setting 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.