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Displaying posts with tag: galera (reset)
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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RDS Aurora MySQL Failover

Right now Aurora only allows a single master, with up to 15 read-only replicas.

Master/Replica Failover

We love testing failure scenarios, however our options for such tests with Aurora are limited (we might get back to that later).  Anyhow, we told the system, through the RDS Aurora dashboard, to do a failover. These were our observations:

Role Change Method

Both master and replica instances are actually restarted (the MySQL uptime resets to 0).

This is quite unusual these days, we can do a fully controlled role change in classic asynchronous replication without a restart (CHANGE MASTER TO …), and Galera doesn’t have read/write roles as such (all instances are technically writers) so it doesn’t need role changes at all.

Failover Timing

Failover between running instances takes about 30 seconds.  This is in line with information provided in the …

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Exploring Amazon RDS Aurora: replica writes and cache chilling

Our clients operate on a variety of platforms, and RDS (Amazon Relational Database Service) Aurora has received quite a bit of attention in recent times. On behalf of our clients, we look beyond the marketing, and see what the technical architecture actually delivers.  We will address specific topics in individual posts, this time checking out what the Aurora architecture means for write and caching behaviour (and thus performance).

What is RDS Aurora?

First of all, let’s declare the baseline.  MySQL Aurora is not a completely new RDBMS. It comprises a set of Amazon modifications on top of stock Oracle MySQL 5.6 and 5.7, implementing a different replication mechanism and some other changes/additions.  While we have some information (for instance from the “deep dive” by AWS VP Anurag Gupta), the source code of the Aurora modifications …

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Enterprises choose Galera Cluster. Read why.

“Our three megastores’ and webshop’s combined revenue was 432 million euros in the year 2017. Galera Cluster has been the cornerstone of the system, secured our sales and supported our growth.”

“MySQL master/slave setup was just too fragile and needed regular work to fix each time the slave got out of sync. Now with Galera we’ve found that even if we take a node offline for a while, it re-syncs automatically and without intervention.”

“The big plus is that all nodes have exact the same information, and no node is running for even a fraction of a second behind. This will also mean that no information will be lost!”

 

READ MORE CASE STUDIES AND TESTIMONIALS

Percona XtraDB Cluster 5.7.20-29.24 Is Now Available

Percona announces the release of Percona XtraDB Cluster 5.7.20-29.24 (PXC) on January 26, 2018. Binaries are available from the downloads section or our software repositories.

NOTE: Due to new package dependency,
Ubuntu/Debian users should use apt-get dist-upgrade, apt upgrade, or apt-get install percona-xtradb-cluster-57 to upgrade.

Percona XtraDB Cluster 5.7.20-29.24 is now the current release, based on the following:

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How to convert galera node to async slave and vice-versa with MariaDB Galera Cluster.

Recently, I was working with one of our customer and this is what their requirement as they want to automate this process for converting galera node to async slave and make async slave to galera node without shutting down any server. ———- Here are the steps for how to do that. I assumes that you already have working 3 nodes galera cluster if not, then for the testing purpose you can create it from my previous post. setup-three-nodes-mariadb-galera-cluster-on-single-server-with-mysql-sandbox ———- Btw, there is no matter how many nodes you have. Now, create one test1 table and add 3 records in galera cluster.

MariaDB [nil]> select * from test1;
+------+-----------+
| id   | name      |
+------+-----------+
|    1 | nilnandan |
|    2 | joshi     |
|    3 | niljoshi  | …
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