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558 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?

Webinar Replay and Q&A: Galera 3.0 Introduction and Cluster Management - with MySQL 5.6, Global Transaction IDs and WAN

 

Webinar topics:

  • Galera Cluster features and benefits

  • Support for MySQL 5.6

  • Integration with MySQL Global Transaction Identifiers

  • Mixing Galera synchronous replication and asynchronous MySQL replication

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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.

Installing ClusterControl Standby Server

As you might already know, ClusterControl runs on a dedicated host. Failure of the ClusterControl host (or the datacenter it is running in) does not affect your running database cluster, however you cannot manage the cluster during that time. This is inconvenient. To guard against this, it is possible to deploy a standby ClusterControl server and increase the availability of your management infrastructure. 

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Patch Updates and New Version Upgrades of your Database Clusters

Database vendors regularly issue critical patch updates to address software bugs or known vulnerabilities, but for a variety of reasons, organizations are often unable to install them in a timely manner, if at all. Evidence suggests that companies are actually getting worse at patching databases, with an increased number violating compliance standards and governance policies.

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Resources for HA Database Clusters: Latest Updates

For those of you who know Severalnines and maybe use some of our tools & products, you’ll know that we provide our users with a monthly summary of all the resources & tools that we’re publishing. Since this is publicly available material, we thought it’d be useful also for the broader open source database community.

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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. 

Using BitTorrent Sync to Transfer Database Backups Offsite

BitTorrent Sync is a simple replication application providing encrypted bidirectional file transfers that can run behind NAT and is specifically designed to handle large files. By leveraging the simplicity of Bittorrent Sync, we can transfer backup files away from our cluster, enhancing the backups availability and reducing the cost of broken backup, where you can regularly verify your backups off-site.

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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.

Clustering MySQL Backend in OpenStack

OpenStack uses a database to store data for all OpenStack services such as compute nodes available, running instances, state and so on. The DB takes part in every user request, from listing all instances to creating new VMs, so it is central to the operation of OpenStack. In a high availability environment, the database should be clustered so as to avoid a single point of failure (SPOF).