BRARCHIVE :Distributed Scenario

Each ORACLE instance has its own local archive directory. This directory should not reside on a mounted disk.

BRARCHIVE is started locally on the hosts of all ORACLE instances.

In this case, BRARCHIVE works similarly to a configuration without the Parallel Server option. In each case, BRARCHIVE saves the offline redo log files of the local instance. BRARCHIVE can determine these by means of the thread number ( init.ora parameter thread ), which is allocated to every local instance.

If offline redo log files of other instances occur in the local archiving directory, BRARCHIVE also archives these.

Every ORACLE instance has its own volume management controlled by BRARCHIVE. The offline redo log files which were found in the local archiving directory of the corresponding instance are saved on every tape (in exceptions these can be offline redo log files of different instances). The assignment of the offline redo log files to the individual instances can be seen in the file names. The name conventions are defined by the init.ora parameters log_archive_dest and log_archive_format .

log_archive_dest = /oracle/C11/saparch/C11arch

log_archive_format = %t_%s.dbf

%t - Thread number (for identifying the instance)
%s - Log sequence number

The ORACLE placeholder @ (for ORACLE_SID) may not appear in the name of an offline redo log file; this means that it may not appear in either log_archive_dest nor in log_archive_format .

The offline redo log files can be archived either to local tape units (connected to the host of the instance, backup_dev_type = tape ) or to tape units connected to the host of the DDB ( backup_dev_type = pipe ).

Advantages

• The use of BRARCHIVE in this case is similar to its use during a non-OPS configuration.

Disadvantages

• Free disk space must be made available on all instance hosts, so that a local ORACLE backup can be made of the offline redo log files in the archiving directory.

• BRARCHIVE must be started once per ORACLE instance.

• For every instance, a separate BRARCHIVE volume pool must be managed.

• SAP does not recommend this scenario. See
Special Features of BRARCHIVE.

The use of BRARCHIVE in the distributed scenario is useful if a large number of offline redo log files are created on every ORACLE instance, which would nearly fill a volume (tape).

Further Remarks

The offline redo log files are required if the database has to be recovered. Recovery measures should only be performed by an experienced administrator, who is familiar with the OPS-specific behavior of the database system in this case.

Note the following if the offline redo log files are to be restored:

The required offline redo log files must be restored separately for each instance (using SAPDBA or a BRRESTORE call). The target directory for the offline redo log files of all instances is the archiving directory of the instance from which the database system recovery is to be started. Then start the recovery (information about this can be found in the ORACLE documentation).