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Displaying posts with tag: galera (reset)
CVE-2020-15180 – Affects Percona XtraDB Cluster

Galera replication technology, a key component of Percona XtraDB Cluster, suffered from a remote code execution vulnerability. Percona has been working with the vendor since early September on this issue and has made releases available to address the problem.

Applicability

A malicious party with access to the WSREP service port (4567/TCP) as well as prerequisite knowledge of the configuration of the Galera cluster name is required in order to exploit this vulnerability, which leads to remote code execution via the WSREP protocol. 

Fixes are available in Percona XtraDB Cluster versions:

>= 8.0.20-11.2

>= …

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Various Ways to Perform Schema Upgrades with Percona XtraDB Cluster

Schema changes are the big challenges in Galera replication. So, it is recommended to understand the schema changes operation for everyone who uses the Percona XtraDB Cluster (PXB)/Galera clusters. In this blog, I am going to explain the operation and impact of the various schema changes methods used in the PXB/Galera cluster.

  • Schema changes with “wsrep_OSU_method = TOI”
  • Schema changes with “wsrep_OSU_method = RSU”
  • Schema changes with “ONLINE ALGORITHMS”
  • Schema changes with “pt-osc”
  • Schema changes with “gh-ost”

For testing:

  • I have configured the 3-node Percona Xtradb Cluster (8.0.19).
  • Executing read/write load using the sysbench.
mysql> select @@wsrep_cluster_address\G
*************************** 1. row …
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Effortlessly Scaling out Galera Cluster with ProxySQL

A blog series about ProxySQL and Galera…

This post is the first of a series of blogposts on how to easily use ProxySQL to scale-out your application’s database workload on a Galera cluster. This series will explore the main concepts in configuring ProxySQL for Galera across three articles as follows:

– A first introductory post describing the minimal configuration needed for ProxySQL to monitor and manage a Galera Cluster.
– A second post describing how to setup a read/write split configuration for our Galera Cluster, using ProxySQL query rules.
– A third and final post with examples on specific cluster configuration options and more detailed explanations on why and how ProxySQL changes the nodes states based on configuration changes and monitored variables. Requirements

To illustrate how to configure ProxySQL for a Galera Cluster we will use a sample Galera Cluster

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Replication Between Two Percona XtraDB Clusters, GTIDs and Schema Changes

I got this question on the “How to Avoid Pitfalls in Schema Upgrade with Percona XtraDB Cluster (PXC)” webinar and wanted to answer it in a separate post.

Will RSU have an effect on GTID consistency if replication PXC cluster to another cluster?

Answer for this: yes and no.

Galera assigns its own GTID for the operations, replicated to all nodes of the cluster. Such operations include DML (

INSERT/UPDATE/DELETE

 ) on InnoDB tables and DDL commands, executed with default TOI method. You can find more details on how GTIDs work in the Percona XtraDB Cluster in this blog post.

However, DDL commands, executed with RSU method, are …

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Help Drive the Future of Percona XtraDB Cluster

Percona is happy to announce the experimental release of Percona XtraDB Cluster 8.0. This is a major step for tuning Percona XtraDB Cluster to be more cloud- and user-friendly. This is the second experimental release that combines the updated and feature-rich Galera 4, with substantial improvements made by our development team.

Improvements and New Features in Percona XtraDB Cluster

Galera 4, included in Percona XtraDB Cluster 8.0, has many new features. Here is a list of the most essential improvements:

  • Streaming replication to support large transactions
  • The synchronization functions allow action coordination (wsrep_last_seen_gtid, wsrep_last_written_gtid, wsrep_sync_wait_upto_gtid)
  • More granular and improved error logging. wsrep_debug is …
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Cluster Level Consistency in InnoDB Group Replication

When you have multiple database servers working together as nodes in a cluster, it’s beneficial to understand how data consistency is established. In this post, we’re going to take a look at the various cluster consistency levels that you can choose from within InnoDB Group Replication and see how they impact data flow and failure recovery.

Let’s start with a quick refresher on what data consistency is. In a nutshell, consistency is just a way of thinking about how data is duplicated across multiple nodes in a cluster. If you write a row of data to one node, that data is not considered to be consistent within the cluster until it has been written to all of the other participating nodes. Without consistency, it’s possible to write data to one node in the cluster but not see it immediately when reading from another node in the cluster. In some cases, the aforementioned scenario, better known as eventual consistency, is acceptable but …

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Percona XtraDB Cluster 8.0 New Feature: wsrep_sst_auth Removal

The problem

In PXC 5.6 and 5.7, when using xtrabackup-v2 as the SST method, the DBA must create a user with the appropriate privileges for use by Percona XtraBackup (PXB). The username and password of this backup user are specified in the wsrep_sst_auth variable.

This is a problem because this username and password was being stored in plaintext and required that the configuration file be secured.

The PXC 8.0 solution

(This feature is still under development and may change before PXC 8.0 GA)

Because the wsrep_sst_auth is only needed on the donor side to take a backup, PXC 8.0 uses an internal user (created specifically for use by PXC) with a randomly generated password. Since this user is only needed on the donor, the plaintext password is not needed on the joiner …

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Experimental Binary of Percona XtraDB Cluster 8.0

Percona is happy to announce the first experimental binary of Percona XtraDB Cluster 8.0 on October 1, 2019. This is a major step for tuning Percona XtraDB Cluster to be more cloud- and user-friendly. This release combines the updated and feature-rich Galera 4, with substantial improvements made by our development team.

Improvements and New Features

Galera 4, included in Percona XtraDB Cluster 8.0, has many new features. Here is a list of the most essential improvements:

  • Streaming replication supports large transactions
  • The synchronization functions allow action coordination (wsrep_last_seen_gtid, wsrep_last_written_gtid, wsrep_sync_wait_upto_gtid)
  • More granular and improved error logging. wsrep_debug is now a multi-valued variable to assist in controlling the logging, and logging messages have been significantly improved.
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Comparing Replication Technologies for MySQL Clustering: Part 1

Overview

Clustering provides high availability and disaster recovery, along with the ability to read-scale both locally and globally. Some clusters even provide active/active capabilities, which others have a single master.

Real time database replication is a must for clustering and other key business purposes, like reporting. There are a number of replication technologies available for MySQL, and some are even bundled into various solutions. When choosing a replication methodology, it is paramount to understand just how the data moves from source to target. In this blog post, we will examine how asynchronous, synchronous, and “semi-synchronous” replication behave when used for clustering. Also, we will explore how …

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Percona XtraDB Cluster 5.7.27-31.39 Is Now Available

Percona is happy to announce the release of Percona XtraDB Cluster 5.7.27-31.39 on September 18, 2019. Binaries are available from the downloads section or from our software repositories.

Percona XtraDB Cluster 5.7.27-31.39 is now the current release, based on the following:

All Percona software is open-source and free.

Bugs Fixed

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