This article provides information on migrating existing VMFS 5 datastore to VMFS 6 datastore.

VMFS 6 is the new filesystem of vSphere 6.5. The new filesystem supports 512e advanced format drives and is 4098 sector (4K) aligned. It also supports automatic UNMAP, which asynchronously tracks freed blocks and sends UNMAPs to backend storage in background.

VMFS 5 and VMFS 6 can coexist. However, due to the changes done in VMFS 6 metadata structures to make it 4K aligned, you cannot inline/offline upgrade from VMFS5 to VMFS6.

You can leverage the new VMFS 6 capabilities by creating a new VMFS 6 datastore and provisioning new virtual machines to it or migrating the existing virtual machines from VMFS 5 datastore to VMFS 6 datastore.

For additional information on comparison, please refer to the below document.
* Versions of VMFS Datastores - https://docs.vmware.com/en/VMware-vSphere/7.0/com.vmware.vsphere.storage.doc/GUID-7552DAD4-1809-4687-B46E-ED9BB42CE277.html

Note: PowerCLI cmdlet “Update-VmfsDatastore” can be used to update datastore from VMFS 5 to VMFS 6.

For more details and limitations on this cmdlet please refer to PowerCLI version 6.5.4 documentation. 

Prerequisites for datastore migration

• Identify the VMFS datastore that must be upgraded to VMFS 6 file system type. For example, DS-1.
• Identify the name of the vCenter Server and list of all ESX hosts sharing the datastore with credentials.
• All ESX hosts and the vCenter server must be upgraded to vSphere 6.5.
  
  Note: Do not proceed with datastore upgrade until all ESX hosts which share the datastore are upgraded to vSphere 6.5. If you do not upgrade, older ESX hosts lose connectivity to the new VMFS 6 datastore after upgrading. This may impact the business continuity.
   
• Spare datastore with equal or more capacity, which is shared with all ESX hosts. For example, DS-2 in this KB. The DS-2 datastore is used to temporarily host all virtual machines from the DS-1 datastore.

• Windows 2008/2008 R2/2012 on 64bit in a domain environment. The windows host used for launching the utility.
• PowerShell 2.0 or above, with all policies set. vSphere powershell plugins installed. Should be able to launch as Administrator. Execute in 64bit PowerShell environment.

Different deployment use cases and migration steps

1. Perform version check for the vCenter Server and all ESX hosts.
   
   Note: All ESXi hosts and vCenter Server must be of vSphere 6.5. Do not proceed if any one of ESXi hosts is not vSphere 6.5. Proceeding further means business continuity loss and the new datastore is not visible in old ESX hosts.
    
2. Perform all pre checks for free space availability on datastore DS-2. Available space on DS-2 must be equal or more than the datastore DS-1 space.
3. Ensure that the datastore DS-2 is VMFS 6 type.
4. Prepare list of all virtual machines in the vCenter Server’s inventory that are hosted on datastore DS-1.
5. Evacuate the datastore DS-1. For this, migrate all the virtual machines running from datastore DS-1 to datastore DS-2. Storage vMotion operations are performed on these virtual machines.
   
   Perform one migration at a time to avoid disrupting the performance of remaining datacenter entities. Keep track of any migration failures, if any, re-trigger the migration for those virtual machines.
    
6. Ensure that datastore DS-1 is empty by listing files on this datastore.
   
   Note: Proceed further only if datastore DS-1 is empty.
    
7. Unmount datastore DS-1 from all ESX hosts.
8. Delete datastore DS-1.
9. Create a new datastore with the VMFS 6 filesystem using the same lun. For example, DS-1.
10. Trigger a storage rescan operation on all hosts and wait for few minutes for this operation to complete.
11. Move all virtual machines back to datastore DS-1 from datastore DS-2 by performing storage vMotion operation. It is suggested to migrate one virtual machine at a time. Keep track of any migration failures, if any, re-trigger migration for those virtual machines.

1. Perform version check for vCenter Server and all ESX hosts.
   
   Note: All ESXi hosts and vCenter Server must be of vSphere 6.5. Do not proceed if any one of ESXi hosts is not vSphere 6.5. Proceeding further means business continuity loss and the new datastore is not visible in old ESX hosts.
    
2. Perform all pre checks for free space availability on datastore DS-2. Available space on DS-2 must be equal or more than the datastore DS-1 space.
3. Ensure that the datastore DS-2 is VMFS 6 type.
4. Prepare list of all virtual machines in the vCenter Server’s inventory that are hosted on datastore DS-1.
5. Evacuate the datastore DS-1. For this, migrate all the virtual machines running from datastore DS-1 to datastore DS-2. Storage vMotion operations are performed on these virtual machines.
   
   Perform one migration at a time to avoid disrupting the performance of remaining datacenter entities. Keep track of any migration failures, if any, re-trigger the migration for those virtual machines.
    
6. Prepare the list of files (orphaned files, not registered to the vCenter Server’s inventory) present on datastore DS-1.
7. Start moving these files to datastore DS-2 one at a time. It is suggested to use one of the recommended ways to move files on VMFS datastores.
   
   For example, vmkfstools utility on ESX commandline, powershell cmdlets.
    
8. Ensure that datastore DS-1 is empty by listing files on this datastore. Proceed further only if datastore DS-1 is empty.
9. Unmount datastore DS-1 from all the ESX hosts.
10. Delete datastore DS-1.
11. Create a new datastore with the VMFS 6 filesystem using the same lun. For example, DS-1.
12. Trigger a storage rescan operation on all hosts and wait for few minutes for this operation to complete.
13. Move all virtual machines back to datastore DS-1 from datastore DS-2 by performing storage vMotion operation. It is suggested to migrate one virtual machine at a time. Keep track of any migration failures, if any, re-trigger migration for those virtual machines.
14. Move orphaned data files back to datastore DS-2 one at a time. It is suggested to use one of the recommended ways to move files on VMFS datastores.
    
    For example, vmkfstools utility on ESX commandline, powershell cmdlets.

1. Perform version check for vCenter Server and all ESX hosts.
   
   Note: All ESXi hosts and vCenter Server must be of vSphere 6.5. Do not proceed if any one of ESXi hosts is not vSphere 6.5. Proceeding further means business continuity loss and the new datastore is not visible in old ESX hosts.
    
2. Perform all pre checks for free space availability on datastore DS-2. Available space on DS-2 must be equal or more than the datastore DS-1 space.
3. Ensure that the datastore DS-2 is VMFS 6 type.
4. Prepare list of all virtual machines in the vCenter Server’s inventory that are hosted on datastore DS-1.
5. Identify virtual machines and virtual disks that are configured for disk affinity rules and are hosted from datastore DS-1. If automatic storage load balancing is configured in the cluster, change it to manual setting. Make a note of all the storage affinity rules currently configured.
6. Evacuate the datastore DS-1. For this, migrate all the virtual machines running from datastore DS-1 to datastore DS-2. Storage vMotion operations are performed on these virtual machines.
   
   Perform one migration at a time to avoid disrupting the performance of remaining datacenter entities. Keep track of any migration failures, if any, re-trigger the migration for those virtual machines.
    
7. Ensure that datastore DS-1 is empty by listing files on this datastore. Proceed further only if datastore DS-1 is empty.
8. Unmount the datastore DS-1 from all ESX hosts.
9. Delete the datastore DS-1.
10. Create a new datastore with the VMFS 6 filesystem using the same lun. For example, DS-1.
11. Trigger a storage rescan operation on all hosts and wait for few minutes for this operation to complete.
12. Add this datastore back to datastore cluster as earlier.
13. Move all virtual machines back to datastore DS-1 from datastore DS-2 by performing storage vMotion operation. It is suggested to migrate one virtual machine at a time. Keep track of any migration failures, if any, re-trigger migration for those virtual machines.
14. Add all the storage affinity rules back as earlier (from step #5). If automatic storage load balancing is configured in the cluster, change it back to the original setting (automatic mode).

Note: If you have Storage DRS configured in this environment and you are using SDC, you can also use datastore maintenance mode feature to aid in the above steps. See Usecase 5 below for more detailed description on this.

1. Perform version check for vCenter Server and all ESX hosts.
   
   Note: All ESXi hosts and vCenter Server must be of vSphere 6.5. Do not proceed if any one of ESXi hosts is not vSphere 6.5. Proceeding further means business continuity loss and the new datastore is not visible in old ESX hosts.
    
2. Perform all pre checks for free space availability on datastore DS-2. Available space on DS-2 must be equal or more than the datastore DS-1 space.
3. Ensure that the datastore DS-2 is VMFS 6 type.
4. Prepare list of all virtual machines in the vCenter Server’s inventory that are hosted on datastore DS-1.
5. Evacuate the datastore DS-1. For this, migrate all the virtual machines running from datastore DS-1 to datastore DS-2. Storage vMotion operations are performed on these virtual machines.
   
   Perform one migration at a time to avoid disrupting the performance of remaining datacenter entities. Keep track of any migration failures, if any, re-trigger the migration for those virtual machines.
    
6. In virtual machines with multiple virtual disks, in which atleast one disk hosted from datastore DS-1. Migrate only these particular virtual disks to datastore DS-2. Keep a list of such virtual machines and virtual disks.
7. Ensure that datastore DS-1 is empty by listing files on this datastore. Proceed further only if datastore DS-1 is empty.
8. Unmount datastore DS-1 from all ESX hosts.
9. Delete datastore DS-1.
10. Create a new datastore with the VMFS 6 filesystem using the same lun. For example, DS-1.
11. Trigger a storage rescan operation on all hosts and wait for few minutes for this operation to complete.
12. Move all virtual machines back to datastore DS-1 from datastore DS-2 by performing storage vMotion operation. It is suggested to migrate one virtual machine at a time. Keep track of any migration failures, if any, re-trigger migration for those virtual machines.
13. Migrate virtual disks identified in step # 6 back to datastore DS-1.

1. Perform version check for vCenter Server and all ESX hosts.
   
   Note: All ESXi hosts and vCenter Server must be of vSphere 6.5. Do not proceed if any one of ESXi hosts is not vSphere 6.5. Proceeding further means business continuity loss and the new datastore is not visible in old ESX hosts.
    
2. Perform all pre checks for free space availability on datastore DS-2. Available space on DS-2 must be equal or more than the datastore DS-1 space.
3. Ensure that the datastore DS-2 is VMFS 6 type and is empty.
4. Add datastore DS-2 to this datastore cluster.
5. Put datastore DS-1 into maintenance mode. This should start evacuating datastore DS-1 with storage vMotion operations on the virtual machines. You also observe some of virtual machine moving towards datastore DS-2.
6. Ensure that datastore DS-1 is empty by listing files on this datastore. Proceed further only if datastore DS-1 is empty.
7. Unmount datastore DS-1 from all ESX hosts.
8. Delete datastore DS-1.
9. Create a new datastore with the VMFS 6 filesystem using the same lun. For example, DS-1.
10. Trigger a storage rescan operation on all hosts and wait for few minutes for this operation to complete.
11. Add datastore DS-1 back to the Storage Datastore Cluster.
12. Put datastore DS-2 into maintenance mode. This starts evacuating datastore DS-2 with Storage vMotion operations on the virtual machines.
13. Move the datastore DS-2 out of the datastore cluster.
14. Exit maintenance mode for datastore DS-2.

1. Perform version check for vCenter Server and all ESX hosts.
   
   Note: All ESXi hosts and vCenter Server must be of vSphere 6.5. Do not proceed if any one of ESXi hosts is not vSphere 6.5. Proceeding further means business continuity loss and the new datastore is not visible in old ESX hosts.
    
2. Perform version check for ESX server EWSX-1. This ESX host must be vSphere 6.5.
   
   Note: Do not proceed if any one of ESXi hosts is not vSphere 6.5.
    
3. Perform all pre checks for free space availability on datastore DS-2. Available space on DS-2 must be equal or more than the datastore DS-1 space.
4. Ensure that the datastore DS-2 is of VMFS 6 type.
5. Ensure that the datastore DS-2 is visible from host ESX-1.
6. Add ESX-1 to the vCenter Server inventory.
7. Prepare the list of virtual machines in the vCenter Server’s inventory that are hosted on datastore DS-1.
8. Prepare list of virtual machines running from ESX server ESX-1 and hosted on datastore DS-1.
9. Evacuate the datastore DS-1. For this, migrate all the virtual machines running from datastore DS-1 to datastore DS-2 by performing storage vMotion operations on these virtual machines.
   
   Perform one migration at a time to avoid disrupting the performance of remaining datacenter entities. Keep track of any migration failures, if any, re-trigger the migration for those virtual machines.
    
10. Ensure that datastore DS-1 is empty by listing files on this datastore. Proceed further only if datastore DS-1 is empty.
11. Unmount datastore DS-1 from all ESX hosts.
12. Delete datastore DS-1.