Data migration techniques

A system for migrating data comprising:

• a source data storage system including a source device;
• a target data storage system including a target device;
• a host, wherein the host recognizes two paths to access data of a logical device, a first of the two paths being a passive path to the logical device and the other of the two paths being a second paths that is active path for the host to access data of the logical device, wherein the passive path is between the host and the source data storage system, and the active path is between the host and the target data storage system, the active path being used in connection with proxying at least some requests which are requests to perform I/O (input/output) operations directed to the logical device and which are received at the target data storage system from the host, wherein said at least some requests are proxied through the target data storage system to the source data storage system while migrating data for the logical device from the source device to the target device;
• and
• a non-transitory computer readable medium in the target system, wherein the computer readable medium comprises code stored thereon that performs said migrating to migrate data of the logical device from the source device to the target device and wherein during said migrating, I/O operations from the host directed to said logical device are sent over said active path to the target data storage system, wherein said target data storage system is included in a data storage federation and the source data storage system is not included in the data storage federation, the data storage federation including a plurality of data storage systems using at least one federation-wide namespace wherein each identifier in said one federation-wide namespace is unique across the data storage federation.

A non-transitory computer readable medium comprising code stored thereon for migrating data, the non-transitory computer readable medium comprising code that, when executed, performs a method comprising:

• providing a passive path and an active path for a host to access data of a logical device,
• wherein a source data storage system includes a source device and a target data storage system includes a target device and the host recognizes the passive path and the active path as paths to the logical device, the passive path is between the host and the source data storage system, and the active path is between the host and the target data storage system, the active path being used in connection with proxying at least some requests which are requests to perform I/O (input/output) operations directed to the logical device and which are received at the target data storage system from the host, wherein said at least some requests are proxied through the target data storage system to the source data storage system while migrating data for the logical device from the source device to the target device;
• and
• performing said migrating to migrate data for the logical device from the source device to the target device, wherein said migrating is controlled by a migration module executing on the target data storage system that copies data from the source device to the target device and wherein during said migrating, I/O operations from the host directed to said logical device are sent over said active path to the target data storage system, wherein said target data storage system is included in a data storage federation and the source data storage system is not included in the data storage federation, the data storage federation including a plurality of data storage systems using at least one federation-wide namespace wherein each identifier in said one federation-wide namespace is unique across the data storage federation.