When a
drive fails, remirroring to remaining drives is automatic. These features make ASM
ideal for managing a database storage grid and allow youto use cheaper disk systems
while obtaining higher levels of availability and performance.
Oracle Database 11g introduced a fast mirror resynchronization capability enabling
faster recovery from transient failures. ASM can now be set to only resynchronize
changed ASM disk extents for limited duration failures.
Simple Hardware Failover
Oracle recovers automatically from a system crash. The automatic recovery protects
data integrity, critical in a relational database, but also results in downtime as the
database recovers from a crash. When a hardware failure occurs, the ability to
quickly detect a system crash and initiate recovery is crucial to minimizing the associated
downtime.
When an individual server fails, the instance running on that node fails as well.
Depending on the cause, the failed node may not return to service quickly or be
noticed immediately. Either way, companies that wish to protect their systems from
the failure of a node typically employ a cluster of machines to achieve simple hardware
failover.
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