TurboIMAGE/XL Database Management System Reference Manual MPE/iX V6.5 (30391-90011)

Chapter 7 369
Logging and Recovery
The Mirror Database
with which databases, the RESTART of recovery from a backup is not possible. To restart
recovery from a backup, the user needs to restore the tapes containing the following:
• The databases.
• The RESTART file.
• All log files processed since the last successful RESTART. When running DBRECOV,
the tapes containing the log files must be mounted in the correct sequence according
to the tape volume labels.
• If logging to disk, remember to store the log files that were rolled forward since the last
successful RESTART along with the RESTART file and the databases. Logging to disk
makes it easier to keep the log files grouped with the databases and RESTART file
because all the log files can be stored at the same time when recovery is stopped. Use an
MPE/iX STORE command with the "@" option (rather than a DBSTORE) to backup all the
files on a minimum number of tapes. If it is necessary to restart from a backup, all the
necessary files will be together.
Using naming conventions makes storing the files to tape much easier. The logging naming
conventions should be used. For example, if the database is ORDERS, name the logid
ORDERRS (where RS represents RESTART), and the log file ORDER001. The user can store
all the files with one MPE/iX command as follows:
:STORE ORDER @
NOTE To avoid incompatible time stamps, it is important to store the RESTART file at
the same time that the databases are stored. If logging to disk, also make
sure to store all log files processed since the last successful restart.
Restarting DBRECOV
To restart the recovery process after the next log file in the set is transferred, or the
database maintenance is completed, enter the following RUN command:
:RUN DBRECOV.PUB.SYS,RESTART
DBRECOV requests the name of one of the databases in the RESTART file:
WHICH DATABASE?
If the user types in the name of a nonexistent database, another prompt for the database
recorded in the RESTART file appears. Once again enter the name of a database in the
RESTART file. From the database name that is entered, DBRECOV determines the name of
the RESTART file, tries to open it, and restarts the recovery process. If the RESTART file is
successfully opened but is not a RESTART file, the following error message is printed:
filename is not a DBRECOV RESTART file