How to create SRDF pairs between two EMC symmetrix VMAX storage arrays

How to create SRDF pairs between two EMC symmetrix VMAX storage arrays


This article provides step by step configuration procedure to create SRDF pairs between two EMC symmetrix storage arrays. 


1. Establish the replication link between the production site (source) and dr site (destination). The EMC symmetrix VMAX supports GigE RAs that can be used to configure FCIP between two sites. The other alterbatives are DWDM (FC) or use third party solutions such as Brocade 7800s to establish the connectivity between the sites. Click here to find the procedure for configuring FCIP using Brocade san switches.


2. Create an RDF group between two sites. To create RDF group 'testrdfg' with group id 3 and RDF directors 7G between symmetrix id 089 (prod site) and 099 (dr site), execute the command below


symrdf addgrp -label testrg -rdfg 03 -sid 089 -dir 7g -remote_rdfg 03 -remote_sid 099 -remote_dir 7g -gige 


3. Create a text file on the management server as below with a list of source devices against the destination devices. 


In the example, we will be creating an RDF pair from source device 045C on symmetrix id 089 to destination device 0285 on symmetrix id 099. So the text file will look like this


# cat pair.txt
045C         0285


045C and 0285 should have identical device characteristics. For example, if 045C is a striped meta device with 4 hypers of 60GB, then 0285 must be a striped meta of the same size. Click here for the procedure to create and expand striped meta devices. 


4. Create the pair between the source and target devices using the above text file. The command below will create pair between the devices mentioned in the text file from source array 089 using rdf group 3. rdf group 3 is already configured between Sym ID 089 and 099. So the command will pick the destination device 0285 from Sym ID 099 based on the relationship defined in rdfg 3. The commad will create the pairs in Adaptive copy mode. 



symrdf -file pair.txt -sid 089 -rdfg 3 createpair -type RDF1 -invalidate r2 -rdf_mode acp
_disk 


5. Check the status of the pair. You will see suspended status.


symrdf -file pair.txt  -rdfg 3 query -sid 089


6. Start the synchronization of the pairs. Once the below command is completed, execute command in step 5 to verify the status.


symrdf -file pair.txt  -rdfg 2 esta -sid 089


7. Switch the SRDF mode of operation from adaptive copy to Aysnc or sync, depending on the requirements. It is recommended to wait until the pairs are in sync in adaptive copy mode before switching the mode. There are also other caveats in configuring SRDF/A or SRDF/S which I will explain in another post.


symrdf -file pair.txt -rdfg 2 set mode async (or sync)


8. You could also create a disk group and add all source devices into it and then manage the pairs using the dg name. For example, the below commands create 'pair_dg' and add device 045C into it.


symdg create pair_dg -sid 089 -type RDF1
symld -g pair_dg add dev 045C -sid 089


9. Once the dg is created, use the dg name instead of the file name to query the pair status


symrdf -g pair_dg query -sid 089


Please note that you could have as many devices as you wish in the pair.txt file before issuing create device. You should also take precaution and necessary checks to make sure that the R2 devices on the destination array is not in use.


Enjoy!