By helping to control the growth of the SAP database, SAP data archiving plays an important role in maintaining good application performance and reducing the demand placed on system resources. Yet when my company, Macro 4, surveyed SAP user organisations in Europe about their use of SAP archiving, only 43 per cent said it was something they did - in some countries it was as low as 31 per cent. As archiving specialists, naturally we feel it's important that there is a good appreciation of SAP archiving and why it's important. With this in mind I'm planning on regularly blogging about this topic. In this first post I wanted to give a brief explanation of the SAP archiving process and its significance.
Why archive? Managing Data Growth
In SAP, as in any core business system, rapid data growth is just a fact of life. And as data volumes increase, so does the system administration task - not just for the database, but also for the whole supporting IT infrastructure. At the same time the increase in data adds considerably to the processing workload and slows the performance of the Database Management System (DBMS). This in turn adversely impacts interactive and batch performance. In a mature SAP installation, data from historical transactions can account for up to 80 per cent of the total database capacity. This inactive historical information is no longer required for day-to-day business, but unless it’s removed it just sits there clogging up the system. While it would be great to simply delete it, this isn’t possible because access is often still required - for customer service and product support, for example, or to meet audit requirements. So you need two things: firstly, to move older data off the database in order to control data growth and maximise performance and secondly, to keep that data online so that you can access it again whenever you need to. SAP Data Archiving is the only method supported by SAP for doing this.
How does archiving work?
As anyone who has looked into archiving will be well aware, archiving is not simply a matter of identifying data over a certain age and removing it. There are many dependencies between different data that need to be considered in order to maintain data integrity. For example, if a purchase order goods receipt is not fully closed down, then the accompanying invoice data must not be archived. Fortunately SAP has provided a number of archiving programs to make life easier for the user. These are called ‘archiving objects’ and they allow data to be removed cleanly, without impacting current transactions, and without leaving anything behind. Data for archiving is initially retained in the file system. It is only finally deleted from the database once the previously created archive files have been successfully transferred to the archive content server. Removing the data by archiving saves costs in three ways:
- The archived data is highly compressed, so there is a lot less data to store. Typically you need only 20% of the capacity you needed on the live database.
- The data can be stored on a low cost server, and on low cost storage media e.g. SATA disk.
- As data on the live system is also replicated in the development and QA environments, removing the data could easily lead to a three-fold reduction in total database storage requirements.
So there you have it. Regularly archiving historical SAP data helps to maintain fast response times for your SAP users. Having less data in the live system also speeds up backups and batch performance. Additionally, it can help simplify upgrades by reducing the volume of data that needs to be transferred during the upgrade process (I'll come back to how archiving makes upgrades easier in a future post).
