Hi [NAME],   I might not be able to provide much information, but I've read about ME5 that it will automate the reserved space for each configuration. I'm attaching the best practices for ME5 configuration, these are the only ones available: [URL]   I found ME5 general best practice: [URL]   If the documentations are not able to provide you a clear answer, I would suggest contacting the sales and technical support to further analyze your environment needs and provide a solution for your needs.  
We use our ME5084 with 2 virtual pools.  Each pool is about 140TB.  We normally give out 24TB of RDM to virtual machines to use, which they will fill and request another RDM. How much of the 140TB on each pool should we set aside to not be used as storage.  Are there any performance considerations or other considerations we should keep in mind?   I don't want to divide the storage up, have nothing left and find I put myself in a bind.
ME 5084 - Storage Considerations