Applying VMFS resignaturing

Since we are talking about managing storage in vSphere environments in this chapter, I felt we should cover one extra topic here. One of the common tasks in vSphere is VMFS resignature. First, let's try to find out what a VMFS resignaturing task is.

By default, ESXi mounts all the datastores that are visible to the host. Each datastore has a unique UUID that is stored in the datastore superblock. Also, the unique LUN ID is store in the VMFS metadata. When a LUN is replicated, all the information is copied block by block and we get an identical LUN. If the original datastore had an UUID as X, the copied LUN also has an UUID as X.

Consider the case when you want to mount the replicated LUN; ESXi will see a duplicate LUN and will not mount the LUN automatically.

To mount the replicated LUN, we can either force-mount the copy in case we are sure the original is not in use, or we can resignature the copy so that it will have another UUID.

Though there are other ways of...