6.0.1

Table Of Contents
In addition to LUN snapshoing and replication, the following storage device operations might cause ESXi
to mark the existing datastore on the device as a copy of the original datastore:
n
LUN ID changes
n
SCSI device type changes, for example, from SCSI-2 to SCSI-3
n
SPC-2 compliancy enablement
ESXi can detect the VMFS datastore copy and display it in the vSphere Web Client. You have an option of
mounting the datastore copy with its original UUID or changing the UUID to resignature the datastore.
Whether you chose resignaturing or mounting without resignaturing depends on how the LUNs are
masked in the storage environment. If your hosts are able to see both copies of the LUN, then resignaturing
is the recommended method. Otherwise, mounting is an option.
Keep Existing Datastore Signature
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.
Prerequisites
n
Perform a storage rescan on your host to update the view of storage devices presented to the host.
n
Unmount the original VMFS datastore that has the same UUID as the copy you plan to mount. You can
mount the VMFS datastore copy only if it does not collide with the original VMFS datastore.
Procedure
1 In the vSphere Web Client navigator, select vCenter Inventory Lists > Datastores
2 Click the Create a New Datastore icon.
3 Type the datastore name and if required, select the placement location for the datastore.
4 Select VMFS as the datastore type.
5 From the list of storage devices, select the device that has a specic value displayed in the Snapshot
Volume column.
The value present in the Snapshot Volume column indicates that the device is a copy that contains a
copy of an existing VMFS datastore.
6 Under Mount Options, select Keep Existing Signature.
7 Review the datastore conguration information and click Finish.
What to do next
If you later want to resignature the mounted datastore, you must unmount it rst.
Resignature a VMFS Datastore Copy
Use datastore resignaturing if you want to retain the data stored on the VMFS datastore copy.
When resignaturing a VMFS copy, ESXi assigns a new signature (UUID) to the copy, and mounts the copy as
a datastore distinct from the original. All references to the original signature from virtual machine
conguration les are updated.
When you perform datastore resignaturing, consider the following points:
n
Datastore resignaturing is irreversible.
Chapter 16 Working with Datastores
VMware, Inc. 163