MariaDB Galera Cluster - Simple, Transparent, Highly Available
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The document discusses the MariaDB Galera Cluster, highlighting its features such as multi-master replication, automatic node provisioning, and quorum-based failure handling. It emphasizes the advantages of Galera Cluster over traditional MySQL replication and other high-availability solutions, ensuring no data loss and improved performance. Furthermore, it outlines the cluster's compatibility with various environments and provides information on the Galera project and support options.
MariaDB Galera Cluster - Simple, Transparent, Highly Available
- 1. MariaDB Galera Cluster Simple, Transparent, Highly Available Ivan Zora?, CTO -‐ 13.11.2013
- 3. SkySQL •Leading provider of open source databases, services and solutions •Home for the founders and the original developers of the core of MySQL •The creators of MariaDB, the drop-‐in, innovative replacement of MySQL PAGE 3
- 4. Agenda •Welcome and intro •Galera Cluster Short Introduction •Cluster Topologies •Automatic Node Joining (SST IST) •Galera Project •Galera, MariaDB and SkySQL PAGE 4
- 5. Intro to Galera Cluster
- 7. Multi-Master Replication There can be several nodes MySQL MySQL Galera Replication
- 8. Multi-Master Replication There can be several nodes MySQL MySQL Galera Replication MySQL Automatic node provisioning
- 9. Multi-Master Replication Client can connect to any node There can be several nodes MySQL MySQL Galera Replication MySQL Automatic node provisioning
- 10. Multi-Master Replication read & write read & write read & write Read & write access to any node Client can connect to any node There can be several nodes MySQL MySQL Galera Replication MySQL Automatic node provisioning
- 11. Multi-Master Replication read & write read & write read & write Read & write access to any node Client can connect to any node There can be several nodes MySQL MySQL Galera Replication MySQL Automatic node provisioning Replication is synchronous
- 12. Multi-Master Replication read & write read & write read & write Multi-master cluster looks like one big database with multiple entry points MySQL
- 13. Synchronous Replication Transaction is processed locally up to commit time Read & write MySQL MySQL Galera Replication MySQL
- 14. Synchronous Replication Transaction is replicated to whole cluster commit MySQL MySQL a Galera Replication MySQL
- 15. Synchronous Replication Client gets OK status OK MySQL MySQL Galera Replication MySQL
- 16. Synchronous Replication Transaction is applied in slaves MySQL MySQL Galera Replication MySQL
- 17. How node failures are handled Load Balancing MySQL MySQL MySQL Galera Replication
- 18. Quorum Galera uses quorum based failure handling: – When cluster partitioning is detected, the majority partition "has quorum" and can continue – A minority partition cannot commit transactions, but will attempt to re-connect to primary partition – Load Balancing Note: 50% is not majority! => Minimum 3 nodes recommended. Load balancer will notice errors & remove node from pool MySQL MySQL MySQL Galera Replication
- 19. Optimistic Concurrency Control commit commit Trx A Trx B A B Galera Replication
- 20. Optimistic Concurrency Control ● ● ● Transactions process independently in each cluster node Transaction write sets will be replicated at commit time (before commit) Cluster wide conflicts will be resolved and conflict victim must rollback Optimistic Concurrency Control
- 21. Galera vs other HA solutions Solid SAN Galera RAC Data integrity DRBD Galera is like... NDB ● 99.999...% ● MySQL replication without integrity issues or slave lag DRBD/SAN without failover downtime and performance penalty ● ● Poor 99 % Slow MySQL replication Failover downtime Fast Oracle RAC without failover downtime NDB, but you get to keep InnoDB
- 22. Galera Cluster ➢ Synchronous multi-master cluster ➢ Each node full representative of DB ➢ No Single point of failure ➢ For MySQL+InnoDB ➢ 99.99% compatible ➢ 3 or more nodes needed for HA ➢ Automatic node provisioning ➢ Works in LAN / WAN / Cloud No Data Loss No Slave Lag No Failover
- 25. WAN replication ● Works fine ● Use higher timeouts and send windows ● No impact on reads ● No impact within a transaction ● adds 100-300 ms to commit latency ● No major impact on tps ● Quorum between data centers –3 data centers – Distribute nodes evenly
- 26. WAN with MySQL asynchronous replication ● ● ● ● ● You can mix Galera replication and MySQL replication Good option on poor WAN Remember to watch out for slave lag, etc... "Channel failover" if a master node crashes Mixed replication useful when you want async slave (such as time-delayed, filtered, multi-source...)
- 27. Migrating to Galera Clustering MySQL master MySQL master slave hierarchy MySQL slave
- 28. Galera as MySQL Slave MySQL master Add Galera node as normal MySQL slave MySQL slave Galera Node 1
- 29. Galera as MySQL Slave MySQL master Join more nodes in Galera slave cluster MySQL slave Galera Node 1 Galera Node 2 Galera Node 3
- 30. Galera as MySQL Slave MySQL master Move traffic to Galera cluster MySQL slave Galera Node 1 Galera Node 2 Galera Node 3
- 31. Galera as MySQL Slave Drop obsolete MySQL servers Galera Node 1 Galera Node 2 Galera Node 3
- 33. State Transfer Joining node needs to get the current database state ➢ Two choices: ➢ IST: incremental state transfer ➢ SST: full state transfer ➢ If joining node has been part of cluster, and has some previous state, and gcache spans to that, then IST can be used ➢
- 34. State Snapshot Transfer To send full database state ●wsrep_sst_method to choose the method: ➢ mysqldump ➢ rsync ➢ xtrabackup ➢ write your own... ●
- 36. Galera Project ● Galera Cluster for MySQL 5 years development ● Fully open source ● Based on MySQL Community Server ● Active community ● ● ~3 releases per year ● ● Latest release 3.0 MariaDB Galera Cluster
- 37. Galera Replicator on Launchpad 37
- 38. Galera 3.0 • WAN Replication support •Connections between cluster segments (previously it was between all the nodes) •Donors for State Transfer will be searched within the segment first •Weighted quorum calculation • Certification Keys refactoring •Reduced memory footprint •Faster key checks •Larger transactions can run in parallel 38
- 39. Galera 3.0 • GTID Support •MySQL Slaves will see Galera Cluster as one MySQL Master •Pre-ordered Replication •MySQL Replication events and Galera Replication events can be applied without conflicts 39
- 40. Who is using Galera?
- 42. SkySQL Support, Consulting and Training • • • The best services and support from the original developers of MySQL and Galera Customized professional services that adapt to customers’ needs, from the smallest to the largest implementations On site and public training classes delivered by certified trainers who have implemented Galera in many organizations worldwide PAGE 42
- 43. For More Information... • • • • • Information on Galera: www.galera.com Web, Doc & Knowledge Base: www.mariadb.org www.mariadb.com Launchpad: launchpad.net/maria launchpad.net/galera Jira (bugs and development): mariadb.atlassian.net IRC: irc.freenode.net #maria webchat.freenode.net/? randomnick=1&channels=maria PAGE 43