The present invention is directed to a heartbeat apparatus via a remote
mirroring link for a multi-site and a method for using the heartbeat
apparatus. Information is registered in a configuration table, wherein
the configuration table stores host ID information and volume ID
information. The configuration table is configured, access requests from
a host are verified, host activity is recorded, and additional records
are created in the configuration table when a match is found between the
access records and the registered information. In a multi-site having
two, three or more sites in a multi-hoop configuration, a failover
process with remote mirroring pairs is performed by configuring a
correlation between a remote mirroring pair group, an activity monitor
function and an alert function, wherein the alert function is performed
by a host sending status information regarding activity monitoring in a
storage system and retrieving the notification information via a
plurality of data links, and creating a status manage table using the
notification information.