The core of every SAP system is the database that stores all the information acquired and processed by the SAP system. In the face of many hazards and random events, it is vital to protect the functioning of SAP systems. This means that the first thing to be protected is the most critical component of the environment, i.e., the above-mentioned database.
When using the SAP HANA platform, this can be done by means of SAP HANA High Availability Disaster Recovery (HADR).
The majority of advanced users of business technologies are aware that machines may be unreliable. If we store sensitive information on one server only, and this server is physically damaged (fire, short-circuit, failure), this may shut down or damage the database, stopping the business and potentially causing real financial losses and loss of our clients’ trust. This is why the German SAP has proposed the HADR solution, which protects against the adverse consequences of server trouble.
How does it work?
It is simple. The functioning of HADR involves at least two servers between which data are replicated. These servers may (and should) be located far away from each other, at different locations.
If operation is disrupted at the primary location – due to a power failure, fire or other adverse events – the SAP system will be automatically switched over to the standby server, using the replicated SAP HANA platform database. The entire process may be fully automatic and has virtually no effect on the Client’s business.
– Continuity of the Client’s business is ensured,
– No data are lost,
– It is not necessary to recover the database at another location using backup copy files,
– The company does not bear financial consequences of the unavailability of their key systems, e.g., sales systems.
Three ways of implementing the HADR solution
The SAP company meets the Client’s expectations, enabling the use of its solution even on a tight budget and extension of the environment with the increase of requirements for data security.
The basic configuration of the HADR solution should consist of two separated servers running the SAP HANA Platform. The first of this servers is responsible for the routine running of the SAP system. The second server is a standby server where the SAP HANA Platform runs in standby mode. Real-time replication is configured between the servers so that the data in the standby system are up-to-date in the event of failure of the primary server, ensuring business continuity.
Every SAP environment has to consist of at least two systems: a development and test system and a production system. The optimum solution is an additional third system: a test system. If SAP HANA is used, this requires the implementation of at least 2 separate database servers.
The SAP HANA High Availability Disaster Recovery solution can still be used in such a scenario. It is acceptable to use the development and test server as the standby server for the production environment. In such a case, in order to maintain the high availability of the solution, it is recommended that non-production systems be put in a different location from the production systems. The data are replicated into the standby database in real time, similarly to the classical scenario using a production server and a dedicated standby server.
Upon the failure of the primary production system, before switching over to the backup system located in the development and test environment, the system has to be shut down to provide the adequate resources required for the operation of the backup production system.
This reduces the costs of implementation and future maintenance of the hardware architecture without compromising security, high availability and, most importantly, business continuity.
If it is necessary to provide comprehensive protection for the SAP systems based on the SAP HANA platform, it is possible to extend the hardware architecture with further standby servers that may be replicated from other standby servers in real time.
In this scenario, even the failure of two database servers will not disrupt business continuity because the SAP system will still be available to the users by means of the additional standby servers.
SAP continues to develop its products, with particular focus on the SAP HANA Platform. SAP HANA Platform 2.0 offers many improvements, also with respect to high availability.
The most important and, at the same time, the most desirable functionality is the so-called Active/Active (read-enabled). Thus far, the computing power of the standby server was not used until the occurrence of failure, when the standby server took over the role of the primary database server of the SAP system. With the appearance of SAP HANA Platform 2.0, the situation has changed. The replicated data from the production server may be used for business analytics or reporting on the standby server. An additional advantage of this solution is the fact that when the analyses are moved to the standby server, the load of the primary server is reduced, providing additional computing power for the SAP system.
Author: Jarosław Zdanowski, SAP BASIS Consultant, Hicron