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Background documentation System Requirements for a Hot Standby System Locate the document in its SAP Library structure

Database Software

Hot standby stystems can be set up for MaxDB database instances from Version 7.5.08.

Cluster Solution

A cluster solution enables several physical components to be logically linked. A hot standby stystem consists of two or more computers in a cluster configuration.

The cluster software has to provide a special failover mechanism, which enables master and standby components to exchange roles if an error occurs. It is necessary for the hot standby components to be monitored constantly by the cluster software. As the master and standby components each have a separate internal network address within the cluster configuration, the cluster software has to support IP switching.

For the following cluster solution, a Hot standby stystem was tested with MaxDB: IBM High Availability Cluster Multiprocessing for AIX clustering software.

Memory Management System

The volumes of the master and standby components have to be in a memory management system that meets the following requirements:

·        The components can access the log area at the same time.

·        Two different access authorizations to the log area are possible: “Read only” and “Read and write”.

·        Each data volume has its own physical memory area.

·        The data volumes can be addressed with the same name or a corresponding symbolic link can be set up.

·        Consistent copies of the data volumes (“split”) can be created. When a copy is created, the master component can continue to write to its data volume so that downtimes remain minimal. After the split, the data volumes of the master and standby components are completely independent of each other.

·        When standby components are initialized and if an error occurs, large data sets may have to be copied. This is why a memory management system should be set up with which data can be quickly copied and further processed immediately.

The following memory management systems meet these requirements and support the creation of a hot standby stystem with MaxDB: EMC Symmetrix, IBM TotalStorage Enterprise Storage Server (ESS), IBM TotalStorage SAN Volume Controller (SVC).

 

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