Extend Datastore with New LUN

Hello Community,

I'm trying to extend a VMFS 5.58 Datastore with a new LUN i created on a shared FCoE storage, the same storage where the Datastore to extend is located.

When i try to add new storage, the new LUN is there, but on the increase option under the properties of the datastore to extend the LUN doesn't show.

I looked over the storage documentation for my version of ESXi (5.1) and the procedure is correct.

Am I missing some condition that prevents me to use another LUN as an extent volume for a datastore?

Thanks in advanced.

Regards,

Guillermo.-