I'm setting up a VMware VSAN 5.5 POC (can't upgrade to 6.0 yet for various other reasons) and even though each Dell R730 host had 16 drives, only around 10 of them were showing up in the vSphere Webclient to be claimed as a VSAN disk.
The R730's shipped from Dell with the drives setup in a RAID cluster and even though I had deleted the cluster and changed the controller to pass-thru operation, something must've still been present on some of the drives and the existence of any remnants of data on a drive seems to result in the disk not showing up on the VSAN configuration page:
However the drives were present if I would try to make a traditional datastore out of one of them:
So how to solve this?
You can wipe the disks straight from the ESXi console....
1.) First take note of the naa ID of the disks in question, then console into the host.
2.) Then use the "fdisk" command to do the following:
where XXXXXXXXXXXXX would be the rest of the naa ID.
3.) Ignore the "fdisk command is depreciated" message.
then you'll be prompted for a command
4.) Type o and press enter. This command states that you want to create a new empty partition table on the drive, but nothing is actually committed to the drive yet.
5.) Type w and press enter. This writes the change to the drive.
Here is a screenshot showing the above process:
Repeat this for all the drives in question. Rescan the disk controller and the drives should appear available to add to VSAN in the vSphere Webclient: