RDM disks (WD RED 3TB) not correctly seen in Windows

[lapttt]

Hi. I'm quite new to ESXi 5.1. My issue is that I've been trying to create a RDM to pass through into a Windows 8.1 environment without much luck. The reason why I am trying to do this is so that I can pool the disks using StableBit DrivePool.

I have successfully created the RDM mappings for the WD RED 3TB disks using the tutorial here - http://blog.davidwarburton.net/2010/10/25/rdm-mapping-of-local-sata-storage-for-esxi/

And have added them as Mapped Raw LUN disks against a Windows 8.1 VM. Have tried using the same SCSI Controller and a different one (LSI Logic SAS)

Windows can see the disks, however they show up as 0 bytes even after I initialize them.

Can anyone help? Thanks in advance.

[richardsonporto]

Make sure you are using VMFS 5 and presenting the RDM disk in physical mode otherwise the maximum supported RDM disk size on vSphere 5.1 is 2TB minus 512 bytes.

[lapttt]

I haven't had any issues creating the Raw Disk files - they are sitting there with what appears to be the correct size allocation on a local datastore.

I have also added these to the VM as a virtual disk that already exists. Again no issues.

I boot Windows up and have a look in the Windows disk management tool. Can't see that it is 3TB.

I'm not sure where the vmfs5 comes into it as I am mapping the physical drive straight through?

[Bigfrank83]

Interesting post - I currently run 4 x 1TB WD Green drives in RDM mode to Server 2012 and works great.

I have just ordered 2 x 3TB WD Red to replace 2 of the drives but seems like I may have made a mistake and should have gone for the 2TB version. Have you managed to get this working yet? The drives will be here tomorrow so before attempting to get this working, I may just send them straight back.

[Bigfrank83]

Any news on this?

I have just recently installed my 3TB drives and get the same issues.

May have to invest in a NAS now to get around this. Not keen on Formatting to VMFS as I like the idea of being able to plug the drive in another machine if needed.

[sludgeheaddf]

The resolution is to upgrade VM hardware version to 10 (ESXi 5.5), add a SATA controller (limited to HW v10), add the raw device map to the SATA controller rather than the default LSI SAS. There appears to be some difference between manufacturers firmware and how the 512b sector emulation works.