HP StorageWorks Storage Mirroring for Linux User's Guide (T2558-96078, February 2008)

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Failure monitoring/failover

Failover is a process in which a target machine stands in for a failed source machine. As a result, user and application requests

that are directed to the failed source machine are routed to the target machine.

Storage Mirroring monitors the status of machines by tracking network requests and responses exchanged between source

and target machines. When a monitored machine misses a user-defined number of requests, Storage Mirroring assumes that

the machine has failed. Storage Mirroring then prompts the network administrator to initiate failover, or, if configured, it

occurs automatically.

The failover target assumes the network identity of the failed source. When the target assumes the identity of the source,

user and application requests destined for the source machine or its IP address(es) are routed to the target. After failover,

user and application requests directed to the source machine are routed to the target machine.

When partnered with Storage Mirroring data replication capabilities, failover routes user and application requests with

minimal disruption and little or no data loss. In some cases, failover may be used without data replication to ensure high

availability on a machine that only provides processing services, such as a web server.

Source Name: Marketing

User and application requests sent to

the source by locating the IP address

Before

IP Address: 125.7.82.43

Target Name: Backup

IP Address: 125.7.82.67

Failover

Occurs

After

Failed Source