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Displaying posts with tag: galera (reset)
MariaDB Galera cluster and GTID

In MariaDB 10.2.12, these two don’t yet work together. GTID = Global Transaction ID.  In the master-slave asynchronous replication realm, this means that you can reconnect a slave to another server (change its master) and it’ll happily continue replicating from the correct point.  No more fussing with filenames and offsets (which of course will both differ on different machines).

So in concept the GTIID is “globally” unique – that means it’s consistent across an entire infra: a binlogged write transaction will have the same GTID no matter on which machine you look at it.

  • OK: if you are transitioning from async replication to Galera cluster, and have a cluster as slave of the old infra, then GTID will work fine.
  • PROBLEM: if you want to run an async slave in a Galera cluster, GTID will currently not work. At least not reliably.

The overview issue is …

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Percona XtraDB Cluster 5.7.22-29.26 Is Now Available

Percona announces the release of Percona XtraDB Cluster 5.7.22-29.26 (PXC) on June 29, 2018. Binaries are available from the downloads section or our software repositories.

Percona XtraDB Cluster 5.7.22-29.26 is now the current release, based on the following:

Deprecated

The following variables …

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Percona XtraDB Cluster 5.6.40-26.25 Is Now Available

Percona announces the release of Percona XtraDB Cluster 5.6.40-26.25 (PXC) on June 20, 2018. Binaries are available from the downloads section or our software repositories.

Percona XtraDB Cluster 5.6.40-26.25 is now the current release, based on the following:

All Percona software is open-source and free. …

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PXC loves firewalls (and System Admins loves iptables)

Let them stay together.

In the last YEARS, I have seen quite often that users, when installing a product such as PXC, instead of spending five minutes to understand what to do just run

iptables -F

  and save.

In short, they remove any rules for their firewall.

With this post, I want to show you how easy it can be to do the right thing instead of putting your server at risk. I’ll show you how a slightly more complex setup like PXC (compared to MySQL), can be easily achieved without risky shortcuts.

iptables is the utility used to manage the chains of rules used by the Linux kernel firewall, which is your basic security tool.
Linux comes with a wonderful firewall built into the kernel. As an administrator, you can configure this firewall with interfaces like ipchains  — which we are not going to cover — and iptables, which we shall talk about.

iptables is …

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MySQL Test Framework for Percona XtraDB Cluster

At my latest webinar “MySQL Test Framework (MTR) for Troubleshooting”, I received an interesting question about MTR test cases for Percona XtraDB Cluster (PXC). Particularly about testing SST and IST.

This post is intended to answer this question. It assumes you are familiar with MTR and can write tests for MySQL servers. If you are not, please watch the webinar recording first.

You can find example tests in any PXC tarball package. They are located in directories

mysql-test/suite/galera

 ,

mysql-test/suite/galera_3nodes

  and

mysql-test/suite/wsrep

 , though that last directory only contains a configuration file.

If you …

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MMUG19: Multi-instances with Galera Cluster and MySQL 8.0 on 25th April in Madrid

The Madrid MySQL Users Group has been a bit quiet recently so we thought it would be good to have a meeting again. The next meeting will take place next on Wednesday, 25th April and will cover Galera Cluster (Presentation by Emanuele Mottola).  We will also talk about MySQL 8.0 and any latest updates that … Continue reading MMUG19: Multi-instances with Galera Cluster and MySQL 8.0 on 25th April in Madrid

Percona XtraDB Cluster 5.7.21-29.26 Is Now Available

Percona announces the release of Percona XtraDB Cluster 5.7.21-29.26 (PXC) on March 2, 2018. Binaries are available from the downloads section or our software repositories.

Percona XtraDB Cluster 5.7.21-29.26 is now the current release, based on the following:

Starting from now, Percona XtraDB Cluster issue …

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Percona XtraDB Cluster 5.6.39-26.25 Is Now Available

Percona announces the release of Percona XtraDB Cluster 5.6.39-26.25 (PXC) on February 26, 2018. Binaries are available from the downloads section or our software repositories.

Percona XtraDB Cluster 5.6.39-26.25 is now the current release, based on the following:

Starting from this release, Percona XtraDB …

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MariaDB version upgrade to 10.1.31 breaks Galera cluster

Recently we faced an issue where the config management software had automatically upgraded the mariadb-server-10.1 package to the latest 10.1.31 version. This upgrade broke the galera cluster setup for this installation.

I’ve started to recreate this issue in my local lab setup and I managed to reproduce this problem.

I have created a 3 node galera setup: galera1 (192.168.55.100), galera2 (192.168.55.101) and galera3 (192.168.55.102). All 3 servers run MariaDB-10.1.30. Galera replication is working fine.

This is the basic galera config:

# cat /etc/mysql/conf.d/cluster.cnf
#########################################################
# Galera config
#########################################################

[mysqld]
wsrep_on                                  = ON
wsrep_provider                            = /usr/lib/libgalera_smm.so
wsrep_provider_options                    =
wsrep_cluster_name                        = …
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RDS Aurora MySQL and Service Interruptions

In Amazon space, any EC2 or Service instance can “disappear” at any time.  Depending on which service is affected, the service will be automatically restarted.  In EC2 you can choose whether an interrupted instance will be restarted, or left shutdown.

For an Aurora instance, an interrupted instance is always restarted. Makes sense.

The restart timing, and other consequences during the process, are noted in our post on Aurora Failovers.

Aurora Testing Limitations

As mentioned earlier, we love testing “uncontrolled” failovers.  That is, we want to be able to pull any plug on any service, and see that the environment as a whole continues to do its job.  We can’t do that with Aurora, because we can’t control the essentials:

  • power button;
  • reset switch;
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