Restoring with Partial-AMPs - TARA/ABU

Teradata Archive/Recovery Utility Reference

Product
TARA/ABU
Release Number
15.10
Language
English (United States)
Last Update
2018-10-07
dita:id
B035-2412
lifecycle
previous
Product Category
Teradata Tools and Utilities

If restoring from a non-cluster multi-stream archive and the target system has fewer available streams (data transfer devices) than the source system, then the restore must be broken down into multiple parts in order to restore all of the data from the archive. This is a “Partial-AMPs Restore” and is similar to a cluster restore.

For example, you can perform a six-stream multi-stream archive on a source system if that system has six tape drives available on it. To restore that six-stream archive to a target system that only has three tape drives available, run two three-stream restore jobs in order to restore all of the data from the six-stream archive. The first restore job could restore streams #1-#3, where stream #1 would be the master stream and streams #2 and #3 would be the child streams. Stream #1 in the first restore job should be Stream #1 from the archive job.The second restore job would restore streams #4-#6, where stream #4 would 'act' as the master stream and streams #5 and #6 would be the child streams.

Similar to a cluster restore, when doing a Partial-AMPs restore, you must run with the NO BUILD option so that Teradata ARC does not attempt to build the restored tables after each restore job. When all of the restore jobs have run and all of the data has been restored, run a standalone BUILD job to build the tables involved in the restore. The BUILD job moves the tables out of the 'restoring' state to allow external applications to access the table data.

When using a Partial-AMP restore to restore database DBC to a target system, the restore is only supported in 'non-catalog' mode. Therefore, do not specify either the CATALOG or CATALOGFILE runtime parameters (or their synonyms) when doing a Partial-AMP restore of database DBC.

When using a Partial-AMP restore to migrate data to a target system that is running with a different database version than the source system, special care must be taken based on the hash function on the source and target systems, otherwise the restore could cause the database to restart:

1 If the hash functions between the two Teradata Database versions is the same, the NOSORT runtime parameter must be used on the restore job(s).

2 If the hash function between the two Teradata Database versions is different, Teradata ARC determines if running the Partial-AMPs restore could cause the Teradata Database to restart. If no, the Partial-AMPs restore is allowed to continue. If yes, Teradata ARC aborts the job with the following error message:

*** Failure ARC1280:Partial AMP RESTORE/COPY not allowed when re‑hashing data.

Note: These restrictions only apply during Partial‑AMP Restores and Partial‑AMP Copies.