As a part of data center readiness, with the SAP HANA platform, one can easily set up high availability (HA) and disaster recovery (DR) operations. By getting rid of the fault tolerance or single points of failure and supporting the recommencement of system operations after system failure with fault resilience or least business loss High Availability of the SAP HANA platform is achieved.
Redundancy is the basic thing to attain high availability, which includes:
Data Center Redundancy
Against failure-related outages SAP HANA offers numerous stages of protection:
- Hardware Redundancy: Numerous software and network components, such as enterprise grade error-correcting memories, fans and redundant power supplies, uninterrupted power supply (UPS) and fully redundant network routers and switches and layers of redundant hardware are offered by SAP HANA appliance vendors. To assure writing even if the power gets down batteries are used by disk storage systems and to recover automatically from disk failures, striping and mirroring is used to provide redundancy. To SAP HANA's process all these redundancy solutions are apparent; however, they are a part of the protection in contradiction of system outage because of single component letdowns.
- Software: SUSE Linux Enterprise 11 for SAP (Systems, Applications, Products in Data Processing) is the thing on which SAP HANA is based. A watchdog function is a part of a watchdog task which resumes organized services automatically.
- Persistence: To back system recovery and restart beginning host failures, with least interruption and without data damage SAP HANA carries on savepoints, transaction logs, and snapshots.
- Standby and Failover: For failover, distinct, devoted standby hosts are utilized which increases the accessibility by considerably decreasing the retrieval time from a failure.
To guarantee disaster recovery and high availability of SAP HANA, SAP offers three tools. SAP HANA System Replication is one of the tools. SUSE improves this feature by the application of SUSE Linux Enterprise High Availability Extension and two fresh source agents to enhance the disaster acceptance of SAP HANA Systems.
The following recovery procedures from letdowns are supported by SAP HANA:
- Disaster recovery support: SAP HANA offers three levels of disaster recovery support such as storage replication, backups, and system replication
- Fault recovery support: SAP HANA offers various levels of fault recovery support such as service auto-restart and host auto-failover as well as System replication.
Thus, it can be concluded by stating that High Availability features are vital to customers, and have been at the central of the design of SAP HANA from the time when it started.