高可用性(HA) 3 - Feature Comparison of MySQL HA Solutions

摘自：http://dev.mysql.com/doc/refman/5.1/en/ha-overview.html

mysql网站提供的mysql 复制，drbd， mysql cluster和Oracle VM Template HA方案的比较

Table 15.1. Feature Comparison of MySQL HA Solutions

Requirement	MySQL Replication	DRBD	Oracle VM Template	MySQL Cluster
Availability
Platform Support	All Supported by MySQL Server	Linux	Oracle Linux	AllSupported by MySQL Cluster
Automated IP Failover	No	Yes	Yes	Depends on Connector and Configuration
Automated Database Failover	No	Yes	Yes	Yes
Automatic Data Resynchronization	No	Yes	N/A - Shared Storage	Yes
Typical Failover Time	User / Script Dependent	Configuration Dependent, 60 seconds and Above	Configuration Dependent, 60 seconds and Above	1 Second and Less
Synchronous Replication	No, Asynchronous and Semisynchronous	Yes	N/A - Shared Storage	Yes
Shared Storage	No, Distributed	No, Distributed	Yes	No, Distributed
Geographic redundancy support	Yes	Yes, via MySQL Replication	Yes, via MySQL Replication	Yes, via MySQL Replication
Update Schema On-Line	No	No	No	Yes
Scalability
Number of Nodes	One Master, Multiple Slaves	One Active (primary), one Passive (secondary) Node	One Active (primary), one Passive (secondary) Node	255
Built-in Load Balancing	Reads, via MySQL Replication	Reads, via MySQL Replication	Reads, via MySQL Replication & During Failover	Yes, Reads and Writes
Supports Read-Intensive Workloads	Yes	Yes	Yes	Yes
Supports Write-Intensive Workloads	Yes, via Application-Level Sharding	Yes, via Application-Level Sharding to Multiple Active/Passive Pairs	Yes, via Application-Level Sharding to Multiple Active/Passive Pairs	Yes, via Auto-Sharding
Scale On-Line (add nodes, repartition, etc.)	No	No	No	Yes