Codership Galera (Percona XtraDB and MariaDB Cluster)
Galera is a synchronous replication cluster solution by Codership and also offered by Percona (Percona XtraDB Cluster) and MariaDB (MariaDB Cluster). Galera supports synchronous, multi-primary replication. The synchronous nature enforces updates on the database across the cluster during the commit phase.
Local High Availability (HA)
Zero downtime maintenance is supported. Uses Multi-Master.
Multi-Region and DR
May work with 3rd party technologies but not ideal for business-critical use. Manual rebuild needed for DR failback. Active/Active not supported. No cross-region aware orchestration.
Scalability
Supported but for single-site only.
Performance
Depends on workload - may incur undue latency and locking due to synchronous replication. Load balancing requires application changes and logic or external MySQL proxy.
Deployment and Application Changes
Must install Galera-ized version of MySQL, not native. Works with InnoDB Engine only. Application changes may be necessary and certain SQL contstructs are not supported.
TCO
Free for simple local MySQL HA deployments that do not require support. Costs of 24/7 support from Codership, Percona or MariaDB unknown and they have a 4 hour reponse time. Cost depends on cost per minute of downtime for business-critical or mission-critical application.
MySQL Version
Only Galera versions of MySQL.
Infrastructure and Platform
Supported for all Cloud and on-prem deployments. Can be complicated if multi-region DIY implementation.
Completeness
No MySQL proxy integrated, no multi-region or multi-site aware orchestration.
Maturity
10+ years
Security
Supported. Can be used in PCI and HIPAA compliance.
Management and Monitoring
Can use 3rd party tools such as ClusterControl; or on AWS only - Galera Manager. Alerts can be scripted.