I know this thread is kind of old but I thought I would add my experience. I have serveral R730xd with PERC H730P Mini's in them. On my systems it is not necessary to use HBA mode to get the operating system (ESXi in my case) to recognize the individual drives. You need to go into the PERC config though and mark each physical drive you want to be native accessible to the OS as a non-RAID drive. I have our systems configured with a RAID-1 virtual disk in the PERC and then the remaining 16 drives are configured as non-RAID so they all show up in the OS. In our case we wanted the drives running the ESXi OS to be redundant and then we wanted the other drives to be used and managed by VMware VSAN which needs to see the drives in their native mode. If your not seeing the ability to mark drives as non-RAID then I would suggest upgrading the PERC to the latest firmware and see if that capability shows up. 
Hi all, I have a new Dell R730xd with a PERC H730 card. I've got six 4TB drives connected to it. This works fine in RAID mode, but the card also has support for "HBA mode". That is, the card works as a basic HBA and turns off RAID functionality. When in HBA mode the card software can see the drives, but they never make it through to the OS. The drives are not detected in POST as Non-RAID and there's no option to convert them to Non-RAID. I've talked this through with tech support, who've been really helpful, but we can't find a solution. It seems to work on their server but not mine. So I'm posting this here to see if anybody else is using this configuration, or to find out if anybody has had the same problem and maybe even solved it. Let me know! Thanks,Tim.
Dell R730xd with PERC H730 and Non-RAID/HBA mode