Fail-over storage system

A storage system comprising:

• a plurality of slots usable for each of various kinds of interface controllers, including at least an interface controller that controls a block I/O interface and an interface controller that controls a file I/O interface, said slots having the same shape;
• and
• a disk controller comprising:
• a plurality of first interface controllers and a plurality of second interface controllers;
• a shared memory connected to said first and second interface controllers;
• a disk adapter connected to said shared memory;
• and
• a cache memory connected to said first and second interface controllers, to said shared memory, and to said disk adapter,
• wherein each of said first and second interface controllers includes:
• means that stores a heartbeat mark in a predetermined area in a heartbeat mark storing area of said shared memory at fixed time intervals;
• and
• means that enables said interface controllers to monitor their states, each another by using said heart beat mark stored in said heart beat mark storing area.

A storage system comprising:

• a plurality of slots usable for each of various kinds of interface controllers, including at least an interface controller that controls a block I/O interface and an interface controller that controls a file I/O interface, said slots having the same shape;
• a disk controller comprising:
• a plurality of first interface controllers and a plurality of second interface controllers, wherein some of said first interface controllers are connected to a network managed in the same domain and others of said first interface controllers are connected to a network managed in another domain;
• a shared memory connected to said first and second interface controllers;
• a disk adapter connected to said shared memory;
• a cache memory connected to said first and second interface controllers, to said shared memory, and to said disk adapter;
• first fail-over means for transferring processing of said failed interface controller to a different interface controller included in some of said first interface controllers, when an interface controller included among said first interface controllers connected to a network managed in said same domain fails;
• and
• second fail-over means for transferring processing of said different interface controller to a normal interface controller included among said first interface controllers, when said different interface controller fails;
• and
• a storage unit connected to said disk controller,
• wherein said first fail-over means selects an interface controller whose operating ratio is the lowest among said interface controllers included said first interface controllers and transfers processing of said failed interface controller to said selected interface controller.