Unique identifiers for data replication, migration, failover operations and failback operations

1. A computer implemented method implemented with a processor for assigning a unique identifier for a data item initially deployed at a cluster of nodes of a networked environment, comprising:

determining a unique cluster identifier for a first cluster of a plurality of clusters interconnected over network connections, clusters of the plurality of clusters comprising pluralities of nodes in networked environments, wherein the unique cluster identifier uniquely identifies the first cluster, individual nodes of the pluralities of nodes comprise both hardware and software, the hardware comprising a processor, a memory, and one or more storage devices, the software comprising a hypervisor and a controller virtual machine above the hypervisor, and the controller virtual machine manages at least some of the one or more storage devices as a single logical collection of storage devices comprising a storage pool;

atomically modifying a local counter value at the first cluster of the networked environment, the local counter value comprising a cluster level counter shared by a plurality of nodes that make up the first cluster, wherein the local counter value is atomically modified when a data item is initially deployed at any node of the plurality of nodes that make up the first cluster, the data item being stored on a first storage pool of the first cluster;

forming a unique ID for the data item by appending the unique cluster identifier to the atomically modified local counter value, wherein the data item is immutable after the unique ID for the data item has been formed; and

performing replication or migration of the data item to a second cluster of the plurality of clusters upon determining that the unique ID for the data item is not in a list of unique IDs residing at the second cluster, the data item being replicated at a second storage pool of the second cluster, wherein any identical instance of the data item in the networked environment is associated with the unique ID and a modified instance of the data item is associated with a different unique ID.

2. The method of claim 1 , wherein the unique cluster identifier for the first cluster of the networked environment is determined using a global counter for the networked environment where a value of the global counter is atomically modified each time a new cluster is introduced to the networked environment.

3. The method of claim 1 , wherein the unique cluster identifier is a 64-bit value.

4. The method of claim 1 , wherein the local counter value is a 64-bit value.

5. The method of claim 1 , wherein the replication or migration is performed for a failover operation.

6. The method of claim 5 , wherein the first cluster is a failing cluster and the second cluster is a substitute cluster.

7. The method of claim 1 , wherein the replication or migration is performed for a failback operation.

8. The method of claim 7 , wherein the first cluster is a substitute cluster and the second cluster is a recovered cluster.

9. A computer program product comprising a non-transitory computer usable medium having executable code to execute a method for assigning a unique identifier for a data item initially deployed at a cluster of nodes of a networked environment, the method comprising:

determining a unique cluster identifier for a first cluster of a plurality of clusters interconnected over network connections, clusters of the plurality of clusters comprising pluralities of nodes in networked environments, wherein the unique cluster identifier uniquely identifies the first cluster, individual nodes of the pluralities of nodes comprise both hardware and software, the hardware comprising a processor, a memory, and one or more storage devices, the software comprising a hypervisor and a controller virtual machine above the hypervisor, and the controller virtual machine manages at least some of the one or more storage devices as a single logical collection of storage devices comprising a storage pool;

atomically modifying a local counter value at the first cluster of the networked environment, the local counter value comprising a cluster level counter shared by a plurality of nodes that make up the first cluster, wherein the local counter value is atomically modified when a data item is initially deployed at any node of the plurality of nodes that make up the first cluster, the data item being stored on a first storage pool of the first cluster;

forming a unique ID for the data item by appending the unique cluster identifier to the atomically modified local counter value, wherein the data item is immutable after the unique ID for the data item has been formed; and

performing replication or migration of the data item to a second cluster of the plurality of clusters upon determining that the unique ID for the data item is not in a list of unique IDs residing at the second cluster, the data item being replicated at a second storage pool of the second cluster, wherein any identical instance of the data item in the networked environment is associated with the unique ID and a modified instance of the data item is associated with a different unique ID.

10. The computer program product of claim 9 , wherein the replication or migration is performed for a failover operation, the first cluster is a failing cluster, and the second cluster is a substitute cluster.

11. The computer program product of claim 9 , wherein the replication or migration is performed for a failback operation, the first cluster is a substitute cluster, and the second cluster is a recovered cluster.

12. The computer program product of claim 9 , wherein the unique cluster identifier for the first cluster of the networked environment where the data item is deployed is determined using a global counter for the networked environment, such that a value of the global counter is atomically modified each time a new cluster is introduced to the networked environment.

13. The computer program product of claim 9 , wherein the unique cluster identifier is a 64-bit value.

14. The computer program product of claim 9 , wherein the local counter value is a 64-bit value.

15. A system for assigning a unique identifier for a data item initially deployed at a cluster of nodes of a networked environment, comprising:

a processor;

a memory comprising computer code executed using the processor, in which the computer code, when executed by the processor, implements:

determining a unique cluster identifier for a first cluster of a plurality of clusters interconnected over network connections, clusters of the plurality of clusters comprising pluralities of nodes in networked environments, wherein the unique cluster identifier uniquely identifies the first cluster, individual nodes of the pluralities of nodes comprise both hardware and software, the hardware comprising a processor, a memory, and one or more storage devices, the software comprising a hypervisor and a controller virtual machine above the hypervisor, and the controller virtual machine manages at least some of the one or more storage devices as a single logical collection of storage devices comprising a storage pool;

atomically modifying a local counter value at the first cluster of the networked environment, the local counter value comprising a cluster level counter shared by a plurality of nodes that make up the first cluster, wherein the local counter value is atomically modified when a data item is initially deployed at any node of the plurality of nodes that make up the first cluster, the data item being stored on a first storage pool of the first cluster;

forming a unique ID for the data item by appending the unique cluster identifier to the atomically modified local counter value, wherein the data item is immutable after the unique ID for the data item has been formed; and

performing replication or migration of the data item to a second cluster of the plurality of clusters upon determining that the unique ID for the data item is not in a list of unique IDs residing at the second cluster, the data item being replicated at a second storage pool of the second cluster, wherein any identical instance of the data item in the networked environment is associated with the unique ID and a modified instance of the data item is associated with a different unique ID.

16. The system of claim 15 , wherein:

the unique cluster identifier for the first cluster of the networked environment is determined using a global counter for the networked environment where a value of the global counter is atomically modified each time a new cluster is introduced to the networked environment,

the unique cluster identifier is a 64-bit value and the local counter value is a 64-bit value.

17. The system of claim 15 , wherein the replication or migration is performed for a failover operation, the first cluster is a failing cluster and the second cluster is a substitute cluster.

18. The system of claim 15 , wherein the replication or migration is performed for a failback operation, the first cluster is a substitute cluster, and the second cluster is a recovered cluster.