Hi,
The scenario you have explained is very clear.
I haven't setup SVM DR yet on Prod or test envn., but looking at the SVM DR express guide, one of the conditions mentioned is this:
The source SVM does not contain data protection (DP) volumes and transition data protection (Which you have already highlighted in your query) (TDP) volumes. Basically, until the source volumes are 'RW', SVM DR will not be operational.
SVM DR express guide:
https://library.netapp.com/ecm/ecm_download_file/ECMLP2496254
For example:
Creating a SVM DR is no big deal, but it will have no purpose until it is initialized.
I can create a SVM DR just like that on the DR cluster:
dr_cluster::> vserver create -vserver ds_vs1 -subtype dp-destination
[Job 136] Job succeeded:
Vserver creation completed.
-subtype dp-destination is the key for creating SVM DR.
I can even create the Peering:
dr_cluster::> vserver peer create -vserver ds_vs1 -peer-vserver source_vserver -applications snapmirror
[Job 137] Job succeeded:
Vserver creation completed.
I guess the next step would be to create 'snapmirror relationship' and 'Snapmirror initialize', creating a relationship should be ok, but it's the 'Initialize' phase when both the data and configuration replication starts. This is a key bit and depending upon the -identitypreserve option true/false, it will copy the configuration (Network & NAS settings info) and Data to DR SVM, but even with -identitypreserve false, volume data will be copied.
Coming to your scenario:
1) When you apply precutover (test) read/write mode, the volumes will appear as 'RW', but as this is a test mode, and considering the size (300TB), I will not initialize the SVM DR b'cos this will start the base-line transfer and depending upon the bandwidth and rate, it will prevent me from final cut-over until the base-line is completed. Therefore, I would rather do the necessary testing as needed during the 'test' mode and then do the final cut-over and once the volumes are in RW mode, I will initialize the SVM DR. By-default, it will initialize all the 'RW' volumes, therefore there is an option given which allows you to prevent any-volumes that you don't want to have it DR-protected.
I think if you want to test it , there is no harm, but you may have to stop the replication transfer and delete the relationship when you decide to do final cut-over. Recommendation would be to finish the 7mtt final cut-over and then initialize the SVM DR.
