Notes

Notes on Moving from MySQL to MariaDB and Replication

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Databases
2 minutes
mysql mariadb

NOTTES

  • it’s easier to switch from MySQL to MariaDB
1# (Ubuntu 18.04 LTS - MariaDB 10.3 stable)
2# add repo 
3sudo apt-get install software-properties-common
4sudo apt-key adv --recv-keys --keyserver hkp://keyserver.ubuntu.com:80 0xF1656F24C74CD1D8
5sudo add-apt-repository 'deb [arch=amd64,arm64,ppc64el] http://mirror.poliwangi.ac.id/mariadb/repo/10.3/ubuntu bionic main'
6
7# install
8sudo apt update
9sudo apt install mariadb-server

Replication

  • we probably want a multi-source replication (multiple masters, data is combined into slaves)
  • Galera Cluster is better than multi-source as it has all masters and no slaves. Every node can read+write.
  • Slave databases are not updated in real-time (async transfers)
  • Slave lag is the time it takes to replicate data from master to slave
  • The downside for synchronous write to all masters is that it takes long to write (get an agreement between all master before changes apply)
  • That is why some people setup Galera Cluster, but treat other masters as slaves handling only read ops.

Galera Cluster

  • clustering techonology enabling active-active, true multi-master cluster. each database is a master database
  • Application can read+write from any database node
  • All database nodes contain same data (minimizing data logs)
  • No slave lag, no complex failovers
  • if one master fails, the other nodes continue to serve clients

Keywords

  • multi-mastter(source) replication
  • Topology: infrasttructure of your databaes. Two types: master-master and maser-slave.
  • DBMS: DataBase Management System (control panel). MySQL and Oracle etc. are DBMS

Further reading

  • Galera cluster on Kubernetes

ClusterControl Setup

  • insall ClusterControl (will install MySQL as part of the installation process..)
  • the SSH user has to be the same user and same SSH password on all servers. CloudConrol only asks for one user/password, not separate users for all nodes..
  • Same is the case with MariaDB root passord for all nodes.. Setup your SSH keys before installing ClusterControl > MariaDB. It’ll confirm that the nodes can be reached during the install process.

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