Requirements
| MySQL Replication
| MySQL Replication + Heartbeat
| MySQL Heartbeat + DRBD
| MySQL Cluster
| MySQL + memcached
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Availability
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Automated IP failover
| No
| Yes
| Yes
| No
| No
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Automated database failover
| No
| No
| Yes
| Yes
| No
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Typical failover time
| User/script-dependent
| Varies
| < 30 seconds
| < 3 seconds
| App dependent
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Automatic resynchronization of data
| No
| No
| Yes
| Yes
| No
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Geographic redundancy support
| Yes
| Yes
| Yes, when combined with MySQL Replication
| Yes, when combined with MySQL Replication
| No
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Scalability
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Built-in load balancing
| No
| No
| No
| Yes
| Yes
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Supports Read-intensive applications
| Yes
| Yes
| Yes, when combined with MySQL Replication
| Yes
| Yes
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Supports Write-intensive applications
| No
| No
| Yes
| Yes
| No
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Maximum number of nodes per group
| One master, multiple slaves
| One master, multiple slaves
| One active (primary), one passive (secondary) node
| 255
| Unlimited
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Maximum number of slaves
| Unlimited (reads only)
| Unlimited (reads only)
| One (failover only)
| Unlimited (reads only)
| Unlimited
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