Data Archiving - Requirements & Importing Archving Technology

The main purpose of data archiving is to remove from the database application data that is no longer needed in day-to-day business, with the aim of using resources more efficiently. The following requirements must be taken into account when archiving data:

• Legal requirements: Some kinds of data must be archived so that they can be analyzed at any time in the future, for example data required by the tax authorities. These requirements are subject to the laws of the relevant country. SAP has developed the Data Retention Tool (DART) to enable the US Internal Revenue Service to analyze archived data. The tool includes functions for creating transparent files from archived data and to display this data.

• Technical requirements: From a technical point of view, the question is whether data can still be read long after it has been archived, independent of the hardware used at the time of archiving and the software release status. To guarantee this, SAP Data Archiving stores, together with the actual application data, additional information about the hardware that was used to write the data to the archive and what type of data structure was applied.

• Business requirements: From the business point of view, only those data objects that are no longer required in day-to-day operations may be removed from the database. Therefore, a logic check must be performed to ensure that only data objects belonging to completed business processes can be archived. The high level of integration between R/3 System applications means that the data objects are closely linked. Consequently, it is essential, during archiving, to check whether the removal of a specific data object from the database requires other objects to be archived at the same time.

Important Archiving Terminology

Reorganization

This term has a double meaning in the SAP context. Firstly, it refers to the physical deletion of application data from the database. Secondly, - the true meaning - refers to the reorganization of the database.

In the database, individual table lines containing datasets are stored in database blocks. Deleting, changing and creating datasets creates gaps in the blocks. These gaps can no longer be used. Fragmentation of the database can, in some circumstances, increase the time needed by the system to search for table contents.

Removing the effects of this fragmentation by closing the gaps and thereby enabling more efficient use of the available memory space is what is meant by the term (database) reorganization. This process entails the physical relocation of data from a logical database segment to a contextually-related area in the memory.

Optical archiving

Optical archiving refers generally to the electronic storage and management of documents in storage systems beyond the R/3 System. In most cases, data is stored in optical media such as CDs or WORMs;hence the designation "optical archiving". The term is, however, confusing, and it would be preferable to refer to "imaging" or "electronic data storage" since the term "optical archiving" only describes the physical storage. In principle, all media - and not just optical storage media - can be used that are supported by the storage system that is connected to the SAP System.

Documents that can be stored in this way include

Scanned original documents such as suppliers' invoices

Outgoing documents, such as invoices that are created electronically in R/3 and then forwarded

Print lists created in R/3

In these cases, the documents created are not stored in the R/3 database, but are transferred to document storage systems. The SAP System only maintains links to the externally stored document, thereby enabling access. Documents that are stored (not archived) in this way can be displayed in R/3, but cannot be reloaded into the database. This is due to the different formats in which documents and applications are saved. Whilst application data is stored in the database in a structured format (CI, coded information), scanned documents are stored in NCI format (non-coded information), which cannot be interpreted by the applications.

SAP ArchiveLink

SAP ArchiveLink is an interface that is integrated into the SAP Basis component. It controls communication with storage systems. This standard interface enables access to documents created in SAP applications and stored in a storage system. The storage system must be correctly configured and connected to the R/3 System.

Backup and Restore

Backup refers to the (saved) copy of the database contents that serves as a precaution against data loss. This enables the reinstatement of the database as it was before the system failure. Restore refers to the rewriting of the contents of the backup copy in an emergency.

The following defines more precisely the term Data Archiving:

"Data Archiving is the consistent removal of data objects from the database. This involves writing all table entries that define a data object in archive files outside the database. Consistency of business data is ensured by the SAP archiving programs, which remove all the relevant table entries."