Patent ID: 7124143

Claim:
A data migration method in a system which includes a first storage node including a first logical unit assigned to a first target of an iSCSI protocol, a second storage node coupled to the first storage node, a computer coupled to the first storage node and the second storage node, and a name server coupled to the first storage node, the second storage node and the computer, the data migration method transferring data stored in the first logical unit to the second storage node comprising: accessing from the computer to the first logical unit in the first storage node based on a first relation between the first storage node and the first target by using the iSCSI protocol; indicating the second storage node to configure a second logical unit; configuring the second logical unit in the second storage node; sending the data in the first logical unit, by the first storage node, to the second logical unit in the second storage node; sending, by the first storage node, a first information of the first target to the second storage node; assigning the first target to the second logical unit at the second storage node; notifying, by the second storage node, the name server of a second relation between the second storage node and the first target after assignment of the first target to the second logical unit by using the iSCSI protocol; notifying, by the name server, the computer of the second relation after receiving notification of the second relation from the second storage node by using the iSCSI protocol; accessing from the computer to the second logical unit in the second storage node instead of the first logical unit in the first storage node based on the second relation between the first target and the second storage node after receiving notification of the second relation from the name server by the iSCSI protocol.