Storage volume addition to synchronized read/write accessible storage systems

A method of enabling storage volume addition to a remote data replication facility, comprising:

• implementing the remote data replication facility between two storage arrays, the two storage arrays being synchronized and both storage arrays being read/write accessible to a host such that data written by the host to either of the storage arrays is synchronized on the remote data replication facility to the other of the storage arrays;
• receiving a request from the host, by a first of the storage arrays, to add a storage volume to the remote data replication facility;
• locally creating a first storage volume on the first storage array and setting the first storage volume to be host inaccessible;
• instructing a second of the storage arrays, by the first storage array, to add the storage volume to the remote data replication facility;
• locally creating a second storage volume on the second storage array and setting the second storage volume to be host inaccessible;
• formatting the first storage volume by the first storage array;
• formatting the second storage volume by the second storage array;
• coordinating response to host status inquiries, by the first storage array and second storage array, to not respond with a storage volume status good indication to the host, until both formatting of the first storage volume has completed on the first storage array and formatting of the second storage volume has completed on the second storage array;
• receiving a host storage volume status inquiry from the host by the second storage array;
• determining that formatting of the second storage volume has been completed on the second storage array;
• transmitting a storage volume status inquiry from the second storage array to the first storage array;
• determining that formatting of the first storage volume has been completed on the first storage array;
• responding to the storage volume status inquiry by the first storage array to the second storage array with an indication that formatting of the first storage volume has been completed on the first storage array;
• and
• responding, by the second storage array to the host, with a host storage volume status inquiry response including a storage volume good status.

A synchronous remote data replication facility, comprising:

• a first storage array and a second storage array, the first and second storage arrays being synchronized and both the first and second storage arrays being read/write accessible to a host such that data written by the host to either of the first and second storage arrays is synchronized on the remote data replication facility to the other of the first and second storage arrays;
• each of the first and second storage arrays including one or more processors and one or more storage devices storing instructions that are operable, when executed by the one or more processors, to cause the one or more processors to perform operations comprising:
• receiving a request from the host, by the first storage array, to add a storage volume to the remote data replication facility;
• locally creating a first storage volume on the first storage array and setting the first storage volume to be host inaccessible;
• instructing the second storage array, by the first storage array, to add the storage volume to the remote data replication facility;
• locally creating a second storage volume on the second storage array and setting the second storage volume to be host inaccessible;
• formatting the first storage volume by the first storage array;
• formatting the second storage volume by the second storage array;
• coordinating response to host status inquiries, by the first storage array and second storage array, to not respond with a storage volume status good indication to the host, until both formatting of the first storage volume has completed on the first storage array and formatting of the second storage volume has completed on the second storage array;
• receiving a first host storage volume status inquiry from the host by the first storage array;
• determining a first formatting percentage completion value of the first storage volume on the first storage array;
• transmitting a first storage volume status inquiry from the first storage array to the second storage array;
• determining a second formatting percentage completion value of the second storage volume on the second storage array;
• responding to the first storage volume status inquiry with the second formatting percentage completion value by the second storage array to the first storage array;
• creating a determined completion value, by the first storage array, from the first formatting percentage completion value and second formatting percentage completion value;
• and
• responding, by the first storage array to the host, with a first host storage volume status inquiry response including the determined completion value.