Patent ID: 6859824

Claim:
A storage system comprising: a first storage component comprising a first disk system, the first disk system comprising a first disk control unit and one or more first disk units; and a second storage component comprising a plurality of second disk systems, each second disk system comprising a second disk control units and one or more second disk units, the first and second storage components configured to exchange data over a data network, the first disk system configured to receive a block of data from a host computer and to transmit a data packet to one of the second disk systems, the data packet including the block of data, a time stamp, and a sequence number, each of the second disk systems configured to receive data packets from the first disk system, to receive a limit time value from a predetermined one of the second disk systems based on time stamps and sequence numbers contained in the data packets, to select a candidate data packet from among its received data packets by comparing their associated time stamps to the limit time value, and to write the candidate data packet on one of its second disk units, wherein blocks of data written on the first storage component are written on the second storage component in the same order as on the first storage component.