Hyper-converged flash array system

A host device for a first storage system including a plurality of storage devices each including a nonvolatile semiconductor memory, the host device comprising:

• an internal interface controller connectable to the plurality of storage devices;
• an external network interface connectable to a plurality of storage systems including a second storage system through a storage system network;
• a memory;
• and
• a processor configured to:
• upon receipt of an access command from the second storage system through the storage system network, temporarily store the access command in the memory, and
• control the internal interface controller to transmit the access command to one of the storage devices so that said one of the storage devices accesses the nonvolatile semiconductor memory thereof in accordance with the access command,
• wherein the access command is issued by an operating system executed by the second storage system, which works with an operating system executed by the first storage system in a coordinated manner.