When you restore a vCenter Server environment, take into account these considerations and limitations.
Synchronizing Clocks with NTP Time Synchronization Prior to Backup
Before creating a backup of your vCenter Server deployment, verify that all components on the vSphere network have their clocks synchronized using NTP time synchronization. See Synchronizing Clocks on the vSphere Network.
After a restore, the following configurations revert to the state when the backup was taken.
- Virtual machine resource settings
- Resource pool hierarchy and setting
- Cluster-host membership
- DRS configuration and rules
If the configuration changes, the following might change after a restore.
- Datastore Cluster configuration
- Datastore Cluster membership
- Datastore I/O Resource Management (Storage I/O Control) settings
- Datastore-Datacenter membership
- Host-Datastore membership
Distributed Power Management
If you put a host into standby mode after a backup, the vCenter Server might force the host to exit standby mode when you restore to the backup.
Distributed Virtual Switch
If you use a distributed virtual switch, you are advised to export separately the distributed virtual switch configuration before you restore to a backup. You can import the configuration after the restore. If you omit this consideration, you may lose the changes made to a distributed virtual switch after the backup. For detailed steps, see the VMware Knowledge Base article at http://kb.vmware.com/kb/2034602.
If you delete libraries or items after a backup, you cannot access or use these libraries or items after the restore. You can only delete such libraries or items. A warning message notifies you that there are missing files or folders in the storage backup.
If you create new items or item files after the backup, the Content Library Service has no record of the new items or files after the restore operation. A warning notifies you that extra folders or files were found on the storage backup.
If you create new libraries after the backup, the Content Library Service has no record of the new libraries after restore. The library content exists on the storage backing, but no warning is displayed. You must manually clean the new libraries.
Virtual Machine Life Cycle Operations
- Restoring vCenter Server from a backup that was taken while there are in-flight relocation operations within the vCenter Server instance.
After you restore vCenter Server, the vCenter Server view of the virtual machines may be out of sync with the ESXi view of the virtual machines. This is also true if you performed the backup while there were in-flight operations on vCenter Server. If virtual machines disappear after you restore vCenter Server, you can refer to the following cases.
- The missing virtual machine is located on the destination ESXi host and is registered with the destination ESXi host, but it is not in the vCenter Server inventory. You must manually add the virtual machine to the vCenter Server inventory.
- The missing virtual machine is located on the destination ESXi host, but it is not registered with the destination ESXi host and it is not in the vCenter Server inventory. You must manually register the virtual machine to the ESXi and add the virtual machine back to the vCenter Server inventory.
- The missing virtual machine is located on the destination ESXi host, but it is not registered with the destination ESXi host. Within the vCenter Server instance, the missing virtual machine is marked as orphaned. You must remove the virtual machine from the vCenter Server inventory and add it again.
- Restoring vCenter Server from a backup that has an out of date linked clone virtual machine layout.
If you create a linked clone virtual machine after the backup and you restore vCenter Server from the old backup, then after the restore, vCenter Server does not know about the new linked clone virtual machine until vCenter Server discovers the new linked clone virtual machine. If you remove all existing virtual machines before the new linked clone virtual machine is discovered, then the removal of existing virtual machines corrupts the new linked clone due to missing disks. To avoid this corruption, you must wait until all linked clone virtual machines get discovered by the vCenter Server before you remove virtual machines.
vSphere High Availability
Restoring vCenter Server from a backup may cause it to roll back to older version for the vSphere HA cluster state (HostList, ClusterConfiguration, VM protection state) while the hosts in the cluster have the latest version for the cluster state. Ensure that the vSphere HA cluster state stays the same during restore and backup operations. Otherwise, the following potential problems are present.
- If hosts are added or removed to/from the vSphere HA cluster after backup and before vCenter Server restore, virtual machines could potentially fail over to hosts not managed by the vCenter Server but are still part of the HA cluster.
- Protection states for new virtual machines are not updated on the vSphere HA agents on the hosts which are part of the vSphere HA cluster. As a result, virtual machines are not protected/unprotected.
- New cluster configuration state is not updated on the vSphere HA agents on the hosts which are part of the vSphere HA cluster.
vCenter High Availability
Restoring vCenter Server requires vCenter HA to be reconfigured.
Storage Policy Based Management
Restoring vCenter Server from a backup can lead to the following inconsistencies related to storage policies, storage providers, and virtual machines.
- Registered storage providers after backup are lost.
- Unregistered storage providers after backup reappear and might show different provider status.
- Changes, such as create, delete, or update, performed on storage policies after backup are lost.
- Changes, such as create, delete, or update, performed on storage policy components after backup are lost.
- Default policy configuration changes for datastores performed after backup are lost.
- Changes in the storage policy association of the virtual machine and its disks, and in their policy compliance might occur.
Virtual Storage Area Network
Restoring vCenter Server from a backup may cause inconsistencies in the vSAN. For information how to check vSAN health, see Administering VMware vSAN.
Restoring vCenter Server from a backup might result in missing security patches. You must apply them again after the restore is complete. For information on patching the vCenter Server appliance, see vSphere Upgrade.