2.8.2 Continuing processing in the event of a failure when redundant copies of data have been created

When redundant copies of data have been created, the EADS client accesses the EADS server that stores the target data. The EADS client does not access the EADS servers where copies of the data are stored.

If a failure prevents the EADS client from accessing the EADS server that stores the data, it automatically changes the access target to an EADS server that stores a copy of the data and continues processing.

The following figure shows how data is accessed when EADS server 1 stores the data and how the access target is changed when a failure occurs.

Figure 2‒23: Data access when redundant copies of data have been created and changing the access target in the event of a failure

Important note

The number of EADS servers that make up a cluster must be at least the data multiplicity 2 - 1.

Data consistency is maintained as long as the number of EADS servers that have shut down due to failures is less than the number of data copies plus the original.

For example, if the data multiplicity is 3 and there are five EADS servers and two of the EADS servers are shut down, no data loss occurs.

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