If you do not need to resignature a VMFS datastore copy, you can mount it without changing its signature.
You can keep the signature if, for example, you maintain synchronized copies of virtual machines at a secondary site as part of a disaster recovery plan. In the event of a disaster at the primary site, you mount the datastore copy and power on the virtual machines at the secondary site.
When you mount the VMFS datastore, ESXi allows both reads and writes to the datastore residing on the LUN copy. The LUN copy must be writable. The datastore mounts are persistent and valid across system reboots.
Prerequisites
Launch the vSphere Client and log in to a vCenter Server system.
Before you mount a VMFS datastore, perform a storage rescan on your host so that it updates its view of LUNs presented to it.
Procedure
What to do next
If you later want to resignature the mounted datastore, you must unmount it first.