SVM does not have high IOPS requirements and can be located in SATA DOM (considering you have enough space for it).  And you don't need to create datastore in the disks that will be added to SVM, if you plan to give the entire disk to the SVM. You can add those disks as RDM.  Not sure I understood your question regarding SVM in the shared storage.
[IMAGE]  I have done the scaleIO environment, which is 4 node has installed SDS and SDC. To avoid  SSD capacity  waste, I migrate 4 SVM to SATADOM for release space.  Does SVM put on lower I/O devices will effect scaleIO performance ?What's recommend for SVM location ?  May I migrate the SVM to share storage when scaleIO is ready to create volume?  Any suggestion which to deploy SVM location by official ?[IMAGE]  
SVM location