Abstract: A positive electrode grid body for lead-acid battery includes frame rib including first and second lateral frame ribs and first and second longitudinal frame ribs, an inner rib including a plurality of lateral and longitudinal crosspieces, a plurality of opening portions, and a positive electrode current collection lug connected to the first lateral frame rib. In a region having a length of at least one opening portion or more in the lateral direction of the lateral crosspieces from the first longitudinal frame rib, a cross-sectional area of the plurality of lateral crosspieces located on at least the first lateral frame rib side becomes larger from the second longitudinal frame rib side toward a portion connected to the first longitudinal frame rib.

Abstract: A positive electrode grid body for lead-acid battery includes frame rib including first and second lateral frame ribs and first and second longitudinal frame ribs, an inner rib including a plurality of lateral and longitudinal crosspieces, a plurality of opening portions, and a positive electrode current collection lug connected to the first lateral frame rib. In a region having a length of at least one opening portion or more in the lateral direction of the lateral crosspieces from the first longitudinal frame rib, a cross-sectional area of the plurality of lateral crosspieces located on at least the first lateral frame rib side becomes larger from the second longitudinal frame rib side toward a portion connected to the first longitudinal frame rib.

Abstract: The size of management information pages for storing format management information is minimized and a management size of the management information pages is reduced.

Abstract: A storage system includes a virtual volume, a plurality of RAID groups, a pool unit for managing a plurality of first real storage areas and a controller. If a write command related to the virtual volume is issued from a higher-level device, the controller selects a prescribed second real storage area from among respective second real storage areas included in a prescribed first real storage area, and associates this prescribed second real storage area with a prescribed area inside the virtual volume corresponding to the write command, and which associates one virtual volume with one first real storage area. A migration destination determination unit selects a migration-targeted second real storage area from among the respective second real storage areas associated with the virtual volume, and selects a migration-destination first real storage area, which is to become the migration destination of data stored in the migration-targeted second real storage area.

Abstract: The size of management information pages for storing format management information is minimized and a management size of the management information pages is reduced.

Abstract: A storage system includes a virtual volume, a plurality of RAID groups, a pool unit for managing a plurality of first real storage areas and a controller. If a write command related to the virtual volume is issued from a higher-level device, the controller selects a prescribed second real storage area from among respective second real storage areas included in a prescribed first real storage area, and associates this prescribed second real storage area with a prescribed area inside the virtual volume corresponding to the write command, and which associates one virtual volume with one first real storage area. A migration destination determination unit selects a migration-targeted second real storage area from among the respective second real storage areas associated with the virtual volume, and selects a migration-destination first real storage area, which is to become the migration destination of data stored in the migration-targeted second real storage area.

Abstract: A storage system includes a virtual volume, a plurality of RAID groups, a pool unit for managing a plurality of first real storage areas and a controller. If a write command related to the virtual volume is issued from a higher-level device, the controller selects a prescribed second real storage area from among respective second real storage areas included in a prescribed first real storage area, and associates this prescribed second real storage area with a prescribed area inside the virtual volume corresponding to the write command, and which associates one virtual volume with one first real storage area. A migration destination determination unit selects a migration-targeted second real storage area from among the respective second real storage areas associated with the virtual volume, and selects a migration-destination first real storage area, which is to become the migration destination of data stored in the migration-targeted second real storage area.

Abstract: A storage controller allocates a real storage area to a virtual volume in chunk units each comprising a plurality of pages. In a case where load bias occurs between RAID groups, data reallocation is carried out. A real storage area inside a pool is allocated to a virtual volume 5 in accordance with a write access. A RAID group 6 comprises a plurality of chunks. Each chunk 7 comprises a plurality of pages 8. The pages 8, from within the chunk 7 that has been allocated to the virtual volume 5, are used. A data migration plan is created and stored in page units based on the load of each RAID group. When a host 2 issues a command to a migration-targeted page, data is migrated while this command is being processed.