Home > Storage > PowerMax and VMAX > Storage Admin > Dell EMC PowerMax and VMAX: Non-Disruptive Migration Best Practices and Operational Guide > Add DR to target SG before synchronization
Initially, it was possible to set up SRDF disaster recovery (DR) on the target array using SRDF/A. A later version enabled this use of SRDF/S. In both cases, the NDM synchronization had to be complete before setting up the DR relationship.
Using PowerMaxOS 5978 and Solutions Enabler 9.x, it is possible to setup SRDF/S or SRDF/A from the NDM target array to a disaster recovery site once the migration has entered a migrating state. This reduces significantly the migration process from a customer standpoint. This will also reduce the impact on response time to the host.
As before, select the Storage Group to be migrated and start the NDM create operation. For further guidance on how to migrate the SG, see the section on Metro-based NDM (Using Unisphere for PowerMax or Using Metro NDM using Solutions Enabler 9.x) or Metro-based NDM with precopy (Using Unisphere for PowerMax with precopy or Using Solutions Enabler 9.x with precopy).
In this example, the Storage Group view shows that the migration is 13% completed. In the previous version of NDM, it would have been necessary to let the migration complete to 100% before setting up DR.
From the target array, navigate to the Storage group, highlight it, and select Protect.
In the pop-up window, click Remote Replication using SRDF and click Next.
In the protection configuration window, select the target array, the SRDF mode, and the remote storage group name.
The final confirmation of the planned configuration is displayed. Review and click Run Now.
The result is an SG with DR in an Active/Bias and Synchronous RDF state. Essentially, this cascaded R21 with the R1 being the NDM Source and the R2 being the new DR to 085. For guidance on how to continue with the migration, see the section on Metro-based NDM (Using Unisphere for PowerMax or Using Metro NDM using Solutions Enabler 9.x) or Metro-based NDM with precopy (Using Unisphere for PowerMax with precopy or Using Solutions Enabler 9.x with precopy).
To achieve the same result with Solutions Enabler, perform the following:
symrdf addgrp -label DrSite1 -rdfg 3 -sid 131 -dir 1F:30,2F:30 -remote_rdfg 3 -remote_sid 085 - remote_dir 1F:31, 2F:31
symrdf -file srdf.txt -sid 131 -rdfg 3 -type r1 -establish createpair where the srdf.txt file contains the device pairings
In this SRDF query, the RDFG is shown as 3 which shows that it is on the second leg of the R21. The devices on the DR target are Write disabled to the host and are Synchronized. Some other information such as the 'S' under the mode (M) signifies Synchronous mode.