StorageTek 312564001 manual Data management processing, DB2 table backup and recovery

Further executions of the table migration job for the appropriate DB2 table may subsequently be performed as normal.

Data management processing

Following successful execution of a table migration process, a number of follow-up activities may be required in order to complete the management of migrated and unmigrated data. These activities consist of the following:

•DB2 table backup and recovery

•DB2 table reorganization

•Archive Manager database backup and recovery

DB2 table backup and recovery

There is no change required to backup and recovery processing procedures for tablespaces containing tables which have been enabled for DB2 Manager migration. Image-copies should be taken normally as for non-enabled tables. However, as the size of the tablespaces used for storage of tables may now have been substantially reduced, the length of time taken for image- copy processing will be reduced by a corresponding amount.

Restore of a tablespace containing a migration-enabled table is performed in an identical manner to that of a tablespace containing a non-enabled table. DB2 will restore the 18-byte stubs containing information about migrated rows, as well as restoring non-migrated rows, to the condition they were in at the time the image-copy was taken. The stubs contain all the information necessary to access migrated rows from Archive Manager.

DB2 database reorganization

Tables which have been enabled for migration processing must be defined in a partitioned tablespace (see “Enabling a DB2 table for migration processing” on page 75). This tablespace will have one partition for exclusive storage of migrated row stubs, and one or more partitions for storage of non-migrated rows.

Database reorganization processing should not be performed on the partition containing the migrated row stubs, unless absolutely necessary. Reorganization of this partition will cause all migrated rows to be retrieved from Archive Manager. If Archive Manager objects are held on tape storage only, this is likely to generate a substantial amount of tape activity and could take an excessive length of time to complete. However, all rows stored in this partition will be a fixed 18 bytes in length. In this case, deletion of rows is not likely to cause fragmentation in the tablespace, as deleted space can be re-used as required. The requirement for reorganization of this partition is thus not mandatory.

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