Disk array unit, and method and program for controlling power source in disk array unit

A power source control method in a disk array unit, wherein a plurality of disk array units are connected to one another through a network, the plurality of disk array units being each assigned to one of a plurality of nodes, the power source control method comprising:

• a first step of deciding whether a node concerned is a basic node or an extended node;
• a second step of sensing establishment of communication between respective said nodes by inter-node communication executed through a common signal line which connects each said node;
• and
• a third step of executing, when the node concerned is said basic node, power source control of said extended node based on power source control information set at said basic node,
• wherein said third step includes the sub-steps of:
• when the node concerned is said basic node and power-off operation is input by a power source switch, issuing a power-off request to a main body of said disk array unit;
• recognizing completion of saving of data of a cache memory in the main body of said disk array unit to transmit a power-off allowance notification to said extended node through inter-node communication;
• and
• executing power-off processing of a device power source of said basic node after obtaining a reception response to the power-off allowance notification transmitted from said extended node which has received the power-off allowance notification and has executed power-off processing of a device power source of said extended node,
• wherein each disk array unit comprises the power source switch to control execution of power source control, and said third step further includes the sub-step of:
• determining only an operation of the power source switch mounted on said basic node as valid power source control information and determining an operation of the power source switch mounted on said extended node as invalid power source control information.

A non-transitory computer-readable storage medium storing a power source control program to be executed on a disk array unit in a plurality of disk array units connected to one another through a network, the plurality of disk array units being each assigned to one of a plurality of nodes, wherein said power source control program causes a computer forming said disk array unit to execute:

• a first process for deciding whether a node concerned is a basic node or an extended node;
• a second process for sensing establishment of communication between respective said nodes by inter-node communication executed through a common signal line which connects each said node;
• and
• a third process for executing, when the node concerned is said basic node, power source control of said extended node based on power source control information set at said basic node,
• wherein in said third process,
• when the node concerned is said basic node and power-off operation is input by a power source switch, issuing a power-off request to a main body of said disk array unit, recognizing completion of saving of data of a cache memory in the main body of said disk array unit to transmit a power-off allowance notification to said extended node through inter-node communication, executing power-off process of a device power source of said basic node after obtaining a reception response to the power-off allowance notification which response is transmitted from said extended node which has received the power-off allowance notification and has executed power-off processing of a device power source of said extended node,
• wherein each disk array unit comprises the power source switch, and in said third process,
• only an operation of the power source switch mounted on said basic node is determined as valid power source control information and an operation of the power source switch mounted on said extended node is determined as invalid power source control information.