Recording medium storing control program for decentralized data, storage management program, control node, and disk node

A computer-readable recording medium encoded with a storage management program containing instructions executable on a computer, the computer executing a process of dividing a storage area of a storage device in units of slice and managing the slices, the program causing the computer to execute:

• a number-of-slices counting procedure of referring to a slice assignment information storage which stores slice assignment information indicating an assignment relation of the slices with respect to storage areas of a virtually defined logical disk, counting the number of free slices not assigned to the storage areas of the logical disk, and transmitting number-of-slices information indicating the number of the free slices to a control node which executes a process of assigning the slices to the storage areas of the logical disk;
• a slice identifier transmission procedure of transmitting a slice identifier for identifying each of the free slices to the control node in response to a request from the control node;
• and
• an assignment information update procedure of, when the assignment relation of the slices with respect to the storage areas of the logical disk is notified from the control node, updating the slice assignment information based on the notified assignment relation.

A control node for executing a process of assigning storage areas of storage devices, which are connected respectively to a plurality of disk nodes, to storage areas of a virtually defined logical disk, the control node comprising:

• a number-of-slices collector for collecting number-of-slices information indicating the number of free slices, which are not assigned to the storage areas of the logical disk, from each of the plural disk nodes, which divides the storage area of the corresponding storage device in units of slice and which stores an assignment relation of the slices with respect to the storage areas of the logical disk, and storing the collected number-of-slices information in a number-of-slices storage;
• a disk node selector for, when a process requiring slice assignment to the storage areas of the logical disk generates, referring to the number-of-slices storage, selecting a source disk node from among the disk nodes having the free slices, which serves as a source providing the slice to be assigned, and requesting a slice identifier to identify the free slice for the selected source disk node;
• and
• a slice assigner for receiving the slice identifier from the source disk node, determining an assignment relation of the free slice, which is denoted by the received slice identifier, with respect to the storage areas of the logical disk, and reporting the determined assignment relation to the source disk node.

A disk node for dividing a storage area of a storage device in units of slice and managing the slices, the disk node comprising:

• a slice assignment information storage which stores slice assignment information indicating an assignment relation of the slices with respect to storage areas of a virtually defined logical disk;
• a number-of-slices counter for referring to the slice assignment information storage, counting the number of free slices not assigned to the storage areas of the logical disk, and transmitting number-of-slices information representing the number of the free slices to a control node which executes a process of assigning the slices to the storage areas of the logical disk;
• a slice identifier transmitter for transmitting a slice identifier for identifying each of the free slices to the control node in response to a request from the control node;
• and
• an assignment information updater for, when the assignment relation of the slices with respect to the storage areas of the logical disk is notified from the control node, updating the slice assignment information based on the notified assignment relation.

A process of assigning storage areas of storage devices, comprising:

• connecting the storage devices respectively to a plurality of disk nodes;
• dividing the storage area of a storage device into slices;
• virtually defining a logical disk;
• storing an assignment relation of the slices with respect to the storage areas of the logical disk;
• determining the number of free slices, which are not assigned to the storage areas of the logical disk, from each of the plural disk nodes;
• selecting a source disk node from among the disk nodes having the free slices if a process requiring slice assignment to the storage areas of the logical disk is generated,
• providing the slice to be assigned;
• requesting a slice identifier to identify the free slice for the selected source disk node;
• receiving the slice identification from the source disk node;
• determining an assignment relation of the free slice, which is denoted by the received slice identifier, with respect to the storage areas of the logical disk;
• and
• reporting the determined assignment relation to the source disk node.