Dell EMC Solutions Enabler 9.2 SRDF Family CLI User Guide

In concurrent SRDF, R1 devices are mirrored concurrently to two R2 devices that reside in two remote arrays.

Use the symrdf createpair command to dynamically create concurrent SRDF pairs. This feature allows a second remote mirror to be dynamically added by converting a dynamic R1 device to a concurrent SRDF device. This command can also be used to create a concurrent SRDF device resulting in one SRDF/Metro mirror and one SRDF/A or Adaptive Copy SRDF mirror.

Two remote mirrors are supported for any dynamic R1 device. With Enginuity 5876 or later, both mirrors of a concurrent R1 device can be operating in SRDF/A mode.

Concurrent Operations provides more information.

To dynamically create a second remote mirror using the symrdf createpair command, you must create two separate device files:

• One file containing the first set of R1/R2 device pairs, and
• A second device file listing the same R1 device paired with a different remote R2 device.

Restrictions

The following restrictions apply to creating dynamic concurrent SRDF pairs:

• The SRDF BCVs designated as dynamic SRDF devices are not supported.
• The two SRDF mirrors of the concurrent device must be assigned to different SRDF groups.
• The concurrent dynamic SRDF, dynamic SRDF, and concurrent SRDF states must be enabled on the array.
• With the -restore option, the -remote option is also required if the link status for the first created remote mirror is read/write.
• The following operations are blocked:
  • Adding an SRDF/Metro mirror when the device is already part of an SRDF/Metro configuration.
  • Adding an SRDF/Metro mirror when the device is already an R2 device.
  • Adding an SRDF R2 mirror to a device that has an SRDF/Metro RDF mirror.
  • Adding an SRDF/Metro mirror when the non-Metro RDF mirror is in Synchronous mode.
  • Adding an SRDF mirror in Synchronous mode when the device is already part of an SRDF/Metro configuration

Examples

In a previous example, the createpair command created dynamic device pairs in RDF group 1 using a device file named devicefile. As a result, devices in the first column of the device file were configured as R1 devices on array 55:

symrdf createpair -file devicefile -sid 55 -rdfg 1 -type R1

This example creates SRDF pairs from the list of devices in a second device file, devicefile2

• -type R1 tells SRDF that devices listed in the first column of devicefile2 are R1 type devices on array 55.

  Devices listed in the second-column become the second remote mirror devices.

• -rdfg 2 configures the new SRDF device pairs as members of SRDF group 2.
• -invalidate R1 marks the R1 devices to invalidate for a full copy when the SRDF pair is created.

symrdf createpair -sid 55 -rdfg 2 -file devicefile2 -type R1 -invalidate R1

Use the createpair command with the -restore -remote options to copy the data on the R2 devices to the R1 devices.

In this example:

• -restore begins a full copy from the target to the source, synchronizing the dynamic SRDF pairs in the device file.
• -remote copies data to the concurrent SRDF mirror when the concurrent link is ready.
  NOTE:

  These operations require the remote data copy option, or the concurrent link to be suspended.

symrdf createpair -file devicefile2 -sid 55 -rdfg 2 -type R1 -restore -remote