What is the advantage of System Replication without Data Preload?
System Replication without data preload provides an economic option for organizations that require failure or disaster recover without data-loss, but prefer not to dedicate an identical secondary system. Without data preload, the secondary system uses a very small amount of memory, and can therefore be used for additional purposes, such as development, QA or staging, while standing by. The tradeoff, of course, is that upon take-over, there will be a period of downtime, during which the secondary system is loaded.
How about Planned Downtime (near zero-downtime upgrades)?
The System Replication solution can be used to manage planned downtime scenarios with minimal
interruption to business processes. Simply perform the required maintenance on the secondary first, failover to the secondary. Then, perform the maintenance on the primary and - if required - fail back.
What are typical recovery timelines?
This depends on the solution. Fundamentally, database recovery consists of the following aspects: fault detection, getting the recovery hardware up and running, restarting the database to accept queries, and, to reach full performance, loading most of the tables back into memory.
SAP HANA's Service Auto-Restart and Host Auto-Failover solutions automatically detect faults in less than a minute. For other situations, e.g. full power outage, fault detection will be part of the data center operating procedures.
Using on-line standby hosts avoids the extra effort and time involved in acquiring, connecting, and
rebooting off-line systems, which may take considerable time. Once the hardware is up and running, loading