System Requirements for a Hot Standby
System 
Hardware
· The computers on which the master and standby instances are located use hardware with the same amount of memory and the same type and number of processors.
· Every computer has a unique name.
· All computers are activated.
Operating System
· You have administrator rights on all the computers.
Database Software
· The same database software version is installed on all computers.
· All paths and file names are the same for the master and standby instances (run directory, volumes, trace files, etc.).
· The MaxDB X Servers run on all computers.
Cluster Software
The computers on which the master and standby instances are located are part of a cluster. For information on setting up a cluster, see the manufacturer’s documentation.
Cluster software requirements:
· Failover mechanism that allows the master and standby instance to switch roles in case of errors
· IP switching
The master and standby instances each have their own IP address
Setting up a hot standby system with MaxDB has been tested with the following cluster software: IBM High Availability Cluster Multiprocessing for AIX clustering software.
Memory Management System
The data and log areas of the master and standby instances are in a memory management system. For information on setting up the memory management system, see the manufacturer’s documentation.
Memory management system requirements:
· All instances can access the log area simultaneously.
Ideally, a memory management system should offer two different authorizations for access to the log area: read-only and read and write.
· Every data volume of each database instance involved has its own physical memory area in the memory management system. To avoid collisions of I/O accesses, we recommend separate hard disks in the memory management system.
The data volumes of each instance have the same access path on their respective computers; alternatively, a corresponding symbolic link can be set up.
Consistent copies of the data volumes can be created which after the split can be read and written-to independently of one another. While a copy is being created, the master instance can continue to write to its data volume so that downtimes remain minimal. After the split, the data volumes of the master and standby instances are completely independent of each other.
· Fast copying of data within the memory management system
When standby instances are initialized or if an error occurs, large amounts of data may have to be copied.
· Fast transmission of data between the memory management system and the computers on which the database instances are located
The following memory management systems meet these requirements and support the creation of a hot standby system with MaxDB: EMC Symmetrix, IBM TotalStorage Enterprise Storage Server (ESS), IBM TotalStorage SAN Volume Controller (SVC).
See also: