In an Active/Standby configuration, the backup server is not actively running the SAP DB / MaxDB but stands by in case the primary server experiences a failure. The following scenarios provide specific requirements that must be adhered to when protecting an SAP DB resource instance in Active/Standby configurations.

Active/Standby Scenarios

The typical Active/Standby configurations are explained below in Scenarios 1 and 2.

Scenario 1

The SAP DB IndepDataPath, IndepProgPath and DependPath are installed to one or more shared file systems on the primary server.

  • The paths IndepDataPath, IndepProgPath, and DependPath must be shared between all servers that will protect the resource instance.
  • The directory structure under /usr/spool/sql must be replicated manually to each server in the cluster. This directory structure should not be located on shared storage since it must be accessible from the target server during resource extend operations. (Please disregard for MaxDB 7.8 as this directory no longer exists.)
  • The registry file /etc/opt/sdb must exist on each server in the cluster for MaxDB 7.5.x versions. This file should not be located on shared storage since it must be accessible from the target server during resource extend operations.
  • The database instance data device spaces (data devspaces), log device spaces (log devspaces) and system device spaces (sys devspaces) must reside on a shared disk (either shared file system or shared raw device).

Scenario 2

The SAP DB IndepDataPath and IndepProgPath are installed locally on both servers. The SAP DB DependPath can be installed locally or on a shared file system on the primary server.

  • The directory structure under /usr/spool/sql must exist on all servers with the same permissions as well as the same owner and group. (Please disregard for MaxDB 7.8 as this directory no longer exists.)
  • The registry file /etc/opt/sdb must exist on each server in the cluster for MaxDB 7.5.x versions. This file should not be located on shared storage since it must be accessible from the target server during resource extend operations.
  • The database instance data device spaces (data devspaces), log device spaces (log devspaces) and system device spaces (sys devspaces) must reside on a shared disk (either shared file system or shared raw device).
  • The database instance run directory (RUNDIRECTORY)must be located on shared storage. The value of RUNDIRECTORY can be modified via the DBMCLI command param_directput. If the value of RUNDIRECTORY is modified after the database is created, the database instance must be stopped and restarted to complete the parameter update.
  • The database instance config (<IndepDataPath>/config) directory structure must exist in the same location on all servers in the cluster where the database instance will be protected. In addition, the parameter files for the database instance must be copied from the template (or primary) server to all backup servers in the cluster. The parameter files must be redistributed to all servers in the cluster after any parameter has been updated. The required files are:

config/<db instance>

config/<db instance>.<01>…<N> (Note: There may be multiple .<number> files.)

config/<db instance>.cfg

config/<db instance>.pab

config/<db instance>.upc

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