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Teradata RDBMS Database Administration - NCR

NCR Teradata RDBMS Database Administration - NCR , 2004. - 616 p.
Download (direct link): teradatadatabaseadmin2004.pdf
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Your system uses RAID 5.

On Monday, you archive journals X, Y, and Z.

On Tuesday, you archive journals X, Y, and Z.

On Wednesday, you archive journals X, Y and Z and dump tables X, Y and Z.

On Thursday, two disks fail in a rank on AMP 3.

The Teradata RDBMS includes tables with the following kind of protection:

Fallback with dual before- and after-image (Table X)

Dual before- and after-image (Table Y)

Single before-image and single after-image (Table Z)

To recover, perform the following:

Step Action For More Information
1 Replace the two disks. Contact the TSC for assistance.
2 Initialize the rank. Contact the TSC for assistance.
3 Format RAID 5. Contact the TSC for assistance.
4 Rebuild AMP 3. Use Vproc Manager to format the new disks and build the Teradata RDBMS file system. 'Vproc Manager Utility" in Teradata RDBMS Utilities.
5 Restart the database. "Restarts of the Teradata RDBMS" on page 9-3.
6 Restart processing brings AMP3 online.
7 Perform a Table Rebuild on AMP 3 when it is up. Teradata RDBMS Utilities.

After the disks are configured, the status of each table is now as follows:

Table Status
X All data rows and all before- and after-images are restored
Y The PJ tables are restored, but the primary data table is still missing. You need to perform a restore procedure to restore table Y. See "Restoring Dual Before-and After-Image Protected Tables" on page 8-35.
Z The PJ tables are not restored and the primary data table is missing. You need to restore table Z. For the procedure, see "Restoring Single Before- and AfterImage Protected Tables" on page 8-35.

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Teradata RDBMS Database Administration 8 - 25 Chapter 8: Archiving, Restoring and Recovering Data

Restore-Related Statements

Restoring Dual Before- and After-Image Protected Tables

To fully restore Table Y, follow this procedure:

Step Action
1 Perform a single-AMP RESTORE of AMP 3 using the Tuesday dump of Table Y. Note: You should NOT release read locks.
2 Restore the Wednesday DUMP of Journal Y for the AMP 3.
3 Perform a single-AMP ROLLFOWARD on AMP 3 with the restored journal from Table Y. This replaces the existing rows in Table Y with any after-images made since the last backup on Tuesday.
4 Submit the DELETE JOURNAL statement to delete the restored Journal Y. This deletes all stored images from the restored journal.
5 Perform a single-AMP ROLLFOWARD on AMP 3 with the CURRENT journal from Table Y. This replaces the existing rows in Table Y with any after-images stored in active and/or saved PJ subtables.
6 Release all utility locks.

Restoring Single Before- and After-Image Protected Tables

To restore Table Z, perform the procedure detailed below.

Note: This procedure restores the data table, but does not restore the PJ tables.

Step Action
1 Perform a single-AMP RESTORE of AMP 3 using the Wednesday DUMP of table Z. This restores all of the data rows stored in the archive file from Table Z. You do not need to restore the journal tables for Table Z, since you performed a complete backup of Table Z on the same day as the journal archive. All the changes through Wednesday are in the archive of the entire table. Do not release the utility locks.
2 Perform a single-AMP ROLLFORWARD on AMP 3 using the CURRENT journal from Table Z. This replaces existing table rows with any after-change images stored in the active and / or saved PJ subtables. Any changes in the current journal would have occurred on Thursday before the disk failure.
3 Perform an all-AMPs DUMP of Table Z to protect against a second disk failure in the same cluster. You cannot restore the journal for AMP 3 because you did not specify dual images for Table Z; therefore, another disk failure in the cluster leaves data unrecoverable.

Teradata RDBMS Database Administration

8 - 25 Chapter 8: Archiving, Restoring and Recovering Data

Restore-Related Statements

Step Action
4 Submit a CHECKPOINT WITH SAVE statement. This action: Moves any stored images from the active subtable to the saved subtable of the current journal Initiates the active subtable.
5 Submit a DELETE SAVED JOURNAL statement. This erases the contents of the saved subtable, since the contents are no longer needed.
6 Release the utility locks with the RELEASE LOCKS command.

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Teradata RDBMS Database Administration 8 - 25 Chapter 8: Archiving, Restoring and Recovering Data

Arc Recovery versus FastLoad

Recovery Overview

Some important concepts regarding data recovery operations are:

As with archive and restore operations, you use the ARC utility with permanent journals for data recovery operations.

Roll operations can use either current journals (active and saved subtables) or restored journals (restored subtable).

The CHECKPOINT statement indicates a recovery point in a journal.

The CHECKPOINT WITH SAVE statement saves stored images before a row marker in an active subtable and appends them to the saved subtable.
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