Dell SRDF Introduction

R1 and R2 devices

An R1 device is the member of the device pair at the source (production) site. R1 devices are generally Read/Write accessible to the application host.

An R2 device is the member of the device pair at the target (remote) site. During normal operations, host I/O writes to the R1 device are mirrored over the SRDF links to the R2 device. In general, data on R2 devices is not available to the application host while the SRDF relationship is active. In SRDF synchronous mode, however, an R2 device can be in Read Only mode that allows a host to read from the R2.

In a typical environment:

• The application production host has Read/Write access to the R1 device.
• An application host connected to the R2 device has Read Only (Write Disabled) access to the R2 device.