RDM won't store with VM

[dmeyner22]

I have 4 LUNs presented to my host and 1 VM that is mapping them as RDMs.  Now I can't store the RDM with the virtual machine the option is greyed out and only wants to select local disk on the ESXi host.  The only difference is the other LUNs are 2TB capacity not 2.24TB.

Does anyone have any suggestions in what I might be able to do to map the other LUNs?

Thanks!

[dmeyner22 · Accepted solution]

This is a DR site and I just realized the VMFS was version 3, so after upgrading it to 5 it works as expected.