3 versions of the VMFS file system have been released by VMware for ESXi hosts which include VMFS3, VMFS5, and VMFS6. To fully understand the differences between these VMFS versions check this link.
Today, after the successful installation of ESXi 6.7 on HP DL380 G9 in one organization, we have decided to update their datastores from version 5 to 6. So I read VMware docs for more information about the procedure of upgrading and got some valuable information which here is the summary:
You can leverage the new VMFS 6 capabilities by creating a new VMFS 6 datastore and you cannot online or offline upgrade from VMFS5 to VMFS6. In fact, due to the changes in VMFS 6 metadata structures, it is not possible to upgrade in place and you have to delete and create a new VMFS 6 datastore.
You can have VMFS5 and VMFS6 datastore at same time and also it is possible to migrate the existing virtual machines from VMFS 5 datastore to VMFS 6 datastore.
- If you have Datastore Cluster, put the datastore in maintenance mode to migrate virtual machines to other datastores; in otherwise storage vmotion virtual machine to other datastore manually.
- Perform version check for the vCenter Server and all ESX hosts.
- Ensure that datastore is empty by listing files on this datastore.
- Unmount datastore from all ESX hosts.
- Delete datastore.
- Create a new datastore with the VMFS 6 filesystem using the same LUN name.
- Trigger storage rescans operation on all hosts
- Your datastore has been upgraded to VMFS6 in 7 steps.