How to make VMFS Re-Signature

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When you attempt to mount a device that contains a VMFS datastore copy/storage snapshot, you are given the option to either mount the datastore using the existing signature

or you can assign the datastore a new signature.


ESX detects a LUN as being a snapshot/copy


When a LUN is duplicated by storage snapshot/replication the UUID is also duplicated. When you attempt to mount a duplicated data store you will be given two options:


  1. Keep the existing signature. : Then you have to choose only one of them to be active. also it can be used in DR for example.
  2. Assign a new signature.        : In this case you can make both LUNS running in same time and connect to same host.


It can be done by using vSphere or Command line.


This will list the names of the VMFS datastores and their UUIDs. We can then mount the volumes using:  


#esxcli storage vmfs snapshot list


As these commands are run directly on a host, it is necessary to run them on each host in a cluster, if you want to make the volume available to each


#esxcli storage vmfs snapshot resignature –volume-label=<label>              or         –volume-uuid=<id>


alternative command    to list snapshot detected by ESXi


#esxcfg-volume –l


To re-signiture the volume

#esxcfg-volume –r


To mount the volume without resignaturing (use lower case m for temporary mount rather than persistent)

#esxcfg-volume –M



On your chosen host, browse to the Configuration | Storage tab

Click Add Storage

Select Disk/LUN and click Next

Select the device you wish to add add and click Next

Select Assign new signature or keep existing signature, depending on your needs, and click Next

Click finish. The volume should now be mounted and available in the datastores view.

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