Notes:
- Keeping the existing signature will cause problems in the future, such as preventing the increase of the datastore size, and preventing the datastore from automatically mounting on new hosts, etc. So, "force mounting" (mounting the datastore while keeping the existing signature) is just a temporary step to gain immediate access. After that, please either schedule a maintenance window for the VMs on that datastore and assign the new signature, or migrate the VMs off the datastore so they are not affected by the maintenance.
- On resignature, in addition to assigning a new UUID, ESXi assigns a modified label (i.e. name) to the datastore. The default format of the new label assigned to the datastore is snap-snapID-oldLabel, where snapID is an integer and oldLabel is the label/name of the original datastore.
ESXi 6.x, 7.x, and 8.x
vSphere Client
- Log in to the vSphere Client and navigate to vCenter Home.
- Click Datastores in the menu on the left.
- In the Objects tab click the Create a new datastore icon in the top left.
- Type the datastore name and if required, select the placement location for the datastore.
- Select VMFS as the datastore type.
- From the list of storage devices, select the device that has a specific value displayed in the Snapshot Volume column.
Note: The value present in the Snapshot Volume column indicates that the device is a copy that contains a copy of an existing VMFS datastore. - Under Mount Options, select the desired option (Keep existing, Assign new, Format) for your volume and click Next.
- Review the datastore configuration information.
- Click Finish.
Command line
- Connect to the ESXi host with an SSH session and root credentials
- To list the volumes detected as snapshots, run this command:
esxcli storage vmfs snapshot list
You see output similar to:
49d22e2e-996a0dea-b555-001f2960aed8
Volume Name: VMFS_1
VMFS UUID: 49d22e2e-996a0dea-b555-001f2960aed8
Can mount: true
Reason for un-mountability:
Can resignature: true
Reason for non-resignaturability:
Unresolved Extent Count: 1
- To (force) mount a snapshot/replica LUN that is persistent across reboots, run this command:
esxcli storage vmfs snapshot mount -l label|-u uuid
For example:
esxcli storage vmfs snapshot mount -l "VMFS_1"
esxcli storage vmfs snapshot mount -u "49d22e2e-996a0dea-b555-001f2960aed8"
- To (force) mount a snapshot/replica LUN that is not persistent across reboots, run this command:
esxcli storage vmfs snapshot mount -n -l label|-u uuid
For example:
esxcli storage vmfs snapshot mount -n -l "VMFS_1"
esxcli storage vmfs snapshot mount -n -u "49d22e2e-996a0dea-b555-001f2960aed8"
- To resignature a snapshot/replica LUN (the volume is mounted immediately after the resignature), run this command:
esxcli storage vmfs snapshot resignature -l label|-u uuid
For example:
esxcli storage vmfs snapshot resignature -l "VMFS_1"
esxcli storage vmfs snapshot resignature -u "49d22e2e-996a0dea-b555-001f2960aed8"
- To mount the volume without performing a resignaturing of that volume (this volume is mounted when the ESX host is rebooted), run this command:
esxcfg-volume -M VMFS_UUID|label
For example:
esxcfg-volume -M "VMFS_1"
esxcfg-volume -M "49d22e2e-996a0dea-b555-001f2960aed8"
Note: To view the datastores again in vCenter Server, you may have to perform a rescan of the storage adapters on all ESXi hosts that the datastore is presented to or a refresh of the storage view. If you are having trouble identifying the affected datastore, in the vSphere client, check the storage view of another ESXi host that still has the datastore mounted correctly. This will then allow you to correlate VMFS datastore name with NAA LUN identifier.
Note: Attempting to resignature an already mounted snapshot LUN fails: see fault.VmfsAlreadyMounted error when resignaturing a snapshot LUN