1. A method of migrating data, comprising: executing, on a host, a storage application for providing extended storage functionality at a source storage array; executing, on the source storage array, program code that is an array-side component of the storage application executing on the host, the program code cooperating with the storage application executing on the host to provide the extended storage functionality at the source storage array; generating, by the program code, metadata representing information critical to a proper operation of the storage application executing on the host; associating the metadata with a source virtual array implemented at the source storage array; and initiating, while the host executes the storage application, a data migration event in which data resident in logical units of storage (LUNs) of the source virtual array are copied to LUNs of a destination virtual array implemented at a destination storage array; forwarding, as part of the data migration event, the metadata associated with the source virtual array to the destination storage array, where the metadata is associated with the destination virtual array, to enable the proper operation of the storage application executing on the host to continue after completion of the data migration event.