A common question when using Raw Device Maps (RDMs) is where the multipathing configuration should be completed. Because an RDM provides the ability for a virtual machine to access the underlying storage directly it is often thought that configuration within the VM itself was required. Luckily things are not that complicated and the configuration is no different than that of a VMFS datastore. This means that the VMware Native Multipathing Plugin (NMP) Configuration is responsible for RDM path management and not the virtual machine.
This means that no MPIO configuration is required (or needed) within the virtual machines utilizing RDMs. All of the available paths are abstracted from the VM and the RDM is presented as a disk with a single path. All of the multipathing logic is handled in the lower levels of the ESXi host.
Below is an example of what a pRDM looks like within a Windows VM:
DISKPART> detail disk
PURE FlashArray SCSI Disk Device
Disk ID: {DF47FF82-8901-423E-A774-E2F6B29049E2}
Type : SAS
Status : Online
Path : 0
Target : 1
LUN ID : 0
Location Path : PCIROOT(0)#PCI(1500)#PCI(0000)#SAS(P00T01L00)
Current Read-only State : No
Read-only : No
Boot Disk : No
Pagefile Disk : No
Hibernation File Disk : No
Crashdump Disk : No
Clustered Disk : No
Volume ### Ltr Label Fs Type Size Status Info
---------- --- ----------- ----- ---------- ------- --------- --------
Volume 4 E RDM-Example NTFS Partition 499 GB Healthy