Troubleshooting
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Remote Mirroring of an Oracle Database Using Data Replicator Software
3-11
The RVM Solution is performing as expected. Further testing might be requested by
the customer. You will need to plan this further testing with the customer later.
Troubleshooting
Recovering a database requires a copy of the database from a specific recovery point. This
recovery point is usually the point-in-time capture of a suspended mirror image of the
database while in Hot Backup mode. However, there are conditions where it might not be
possible to mirror the database.
·
The database is too large to mirror.
The database is of such a large size that the initial copy required by mirroring cannot
be accomplished in a reasonable period of time.
·
The database changes often, requiring a full copy each time.
If the schema or the structure of the database changes periodically, mirroring the
changed database might take too long and could result in extended lapses of mirroring.
This lapse might occur when the entire database is changed using bulk-load features,
where transaction logging is suspended during the bulk load. This action necessitates a
full copy of the database before mirroring can begin again.
NOTE
Schema and structural changes might not be consistently recorded in the
transaction logs. This action is intentional and by design in most RDBMSs.
·
Certain types of changes are not recorded in the transaction logs.
Another example is when databases are re-organized for performance reasons.
Tablespaces are re-grouped, indexes are changed, and the logical-to-physical layouts
are changed. None of these types of changes are recorded in the transaction logs.
When these changes are made, you must recopy the database to the secondary site
before you resume mirroring.
In situations where the database cannot be mirrored, establish or move a copy of the
database to the secondary site, and mirror only the logs.
