- Notes, cautions, and warnings
- Preface
- Introduction
- Disaster recovery
- High availability
- Data migration
- SRDF I/O operations
- SRDF write operations
- SRDF read operations
- SRDF/A resilience and performance features
- Management tools
- More information
In other SRDF configurations, devices on the primary array are Read or Write accessible to the application host while devices on the additional arrays are Read Only or Write Disabled. However, in an SRDF high availability configuration:
This shared identity means that the devices appear to the application host as a single, virtual device across the two arrays. Using two devices improves the availability of the data that they contain. One device can become unavailable without impacting on the host application as the second device continues to operate.
Such a configuration, which is known as SRDF/Metro, can be deployed in a single, multipathed host environment, or in a clustered environment as this diagram shows:
High availability describes SRDF high availability and its system configurations in more detail.
SRDF/Metro is available in open systems (FBA) and IBM i D9101 environments only. The mainframe environment has its own high availability configuration called AutoSwap. The publications in the mainframe and GDDR sections of More information contain details of AutoSwap and its capabilities.